JP2017119283A - Regeneration method of casting sand - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a regeneration method of casting sand capable of being inexpensively regenerated to good quality casting sand and performing regeneration work by a small-sized heat-resistant container for combustion in a small scale even when the amount of used casting sand generated in a factory is small.SOLUTION: In a regeneration method of casting sand,: used casting sand SP attached with a shape retention resin P is stored in a heat-resistant container 1 for combustion; a heated gas A is inserted under pressure into the heat-resistant container 1; the shape retention resin P is combusted by the inserted under pressure heated gas A; a combustion part B is sequentially moved from the upper part side of the heat-resistant container 1 to a lower end part; the shape retention resin P is combusted and removed from the casting sand SP by reaching the combustion part B to the lower end part of the heat-resistant container 1; and then a pressurized gas A is released into the atmosphere from the bottom of the heat-resistant container 1.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for regenerating foundry sand in which only the sand particles are regenerated by removing the shape-retaining resin from the foundry sand bonded with the shape-retaining resin to maintain the shape of the mold, such as a sand core.

The sand core, which is an example of the foundry sand, needs to maintain the shape while the molten metal is filled in the mold. Therefore, casting sand, such as sand cores are coupled by a silica sand (S _i O ₂ is the main component) sand particles phenolic resins such as, furan resin or urethane resin or the like shape-retaining resin (binder) Furthermore, a technique is widely used in which the surface of the sand core is similarly coated with a shape-retaining resin such as a phenol resin, and the binding force between the sand particles and the sand particles is increased with such a shape-retaining resin.

  By the way, such casting sand is regenerated by removing the shape-retaining resin mainly from the cost viewpoint and collecting only the sand particles.

  As such a method for reclaiming foundry sand, a fluidized roasting furnace is mainly used as shown in Patent Documents 1 to 3 below.

  The regeneration method using the fluidized roasting furnace includes a step of roasting the foundry sand to which the shape-retaining resin is adhered in the roasting furnace and a step of polishing the roasted foundry sand.

JP-B 57-41295 JP 58-163545 A Patent No. 2905089

  In Patent Documents 1 to 3, it is necessary to regenerate a large amount of foundry sand at once using a very large facility having a height of 6 m or more and a width of 2 m or more. Regenerating the small amount of foundry sand that was generated could not be adopted in terms of regeneration cost. In addition, as described above, complicated processes and long treatments are time consuming, and it is good to process a large amount of foundry sand. ) Was difficult to obtain. Furthermore, since the apparatus has a large and complicated structure, there is a problem that it is not easy to maintain and manage the apparatus.

  The present invention comprises a small regenerator, which can process foundry sand little by little, and is regenerated by a regenerator that has a simple structure for regenerating sand particles of good quality and is easy to maintain. An object of the present invention is to provide a reproduction method that makes it possible.

  Means for solving the above problems will be described with reference numerals in the embodiments described later. The method for reclaiming the foundry sand according to the first aspect of the present invention is a used casting in which a shape-retaining resin P is adhered. The sand SP is accommodated in the heat-resistant container 1 for combustion, the heated gas A is press-fitted into the heat-resistant container 1, the shape-retaining resin P is combusted by the press-fitted heated gas A, and the shape-retained The combustion part B (see FIG. 7) of the resin P for the resin moves sequentially from the upper side to the lower part of the heat-resistant container 1 (as indicated by BA, BB and BC in FIG. 7). The shape retaining resin P is combusted and removed from the foundry sand SP, and the heated gas A is discharged from the bottom of the heat-resistant container 1 into the heat-resistant container 1. The casting sand S from which the shape-retaining resin P has been removed remains. It is characterized in.

  The method for reclaiming foundry sand according to claim 2 is the method for reclaiming foundry sand according to claim 1, wherein the heated gas A is generated by a heated gas generator 2 into which compressed gas is introduced. Features.

  The method for reclaiming foundry sand according to claim 3 is the method for reclaiming foundry sand according to claim 2, wherein the outlet temperature of the heated gas generated by the heated gas generating device 2 from the device is 650 ° C. It is -850 degreeC.

  A method for reclaiming foundry sand according to a fourth aspect of the present invention is the method for reclaiming foundry sand according to claim 2 or 3, wherein the sand is generated by the heated gas generating device 2 and is press-fitted into the heat-resistant container 1 for combustion from the device. The press-fitting temperature of the heated gas A is 350 ° C. to 850 ° C.

  A method for reclaiming foundry sand according to a fifth aspect of the present invention is the method for reclaiming foundry sand according to any one of the second to fourth aspects, wherein the heat-resistant container for combustion 1 is generated by the heated gas generator 2 and is generated from the device. The press-fitting pressure of the heated gas A that is press-fitted inside is 0.3 MPa to 0.6 MPa.

  A method for reclaiming foundry sand according to a sixth aspect of the present invention is the method for reclaiming foundry sand according to any one of the first to fifth aspects, wherein the heat-resistant container for combustion 1 contains spent foundry sand SP therein. A cylindrical main body 3, a top plate 4 that is detachably fixed to the upper end of the cylindrical main body 3, and a bottom plate 5 that is detachably fixed to the lower end of the cylindrical main body 3. 4 is provided with a pressure inlet 6 for pressurizing the heated gas A into the heat-resistant container 1, and the bottom plate 5 is a heated gas that releases only the heated gas A press-fitted into the heat-resistant container 1 into the atmosphere. A discharge hole 7 is provided.

  The method for reclaiming foundry sand according to claim 7 is the method for reclaiming foundry sand according to claim 6, wherein a substantially circular dish-shaped partition frame 8 is fixed to the lower surface of the top plate 4, and the top plate 4 A relay chamber 9 for the heated gas A is formed by being surrounded by the partition frame 8, and the heated gas A is provided in the partition frame 8 from the pressure inlet 6 provided in the top plate 4 via the relay chamber 9. The heat-resistant container 1 is press-fitted from a plurality of press-fitting holes 10.

  The method for reclaiming foundry sand according to claim 8 is the method for reclaiming foundry sand according to claim 7, wherein the press-fitting hole 10 provided in the partition frame 8 is closer to the inner wall of the cylindrical body 3. It is characterized in that a plurality are provided at appropriate intervals in the circumferential direction.

  The method for reclaiming foundry sand according to claim 9 is the method for reclaiming foundry sand according to any one of claims 6 to 8, wherein the heated gas discharge hole 7 provided in the bottom plate 5 is made of heated gas A. It is characterized by comprising innumerable heated gas discharge pores 7a provided in a dotted manner over the entire area of the bottom plate 5 so as to allow passage but prevent passage of foundry sand S.

  The method for reclaiming foundry sand according to claim 10 is the method for reclaiming foundry sand according to any one of claims 6 to 9, wherein the top plate 4 and the bottom plate 5 are fixed to the upper and lower ends of the cylindrical main body 3. The fixing tool 11 to be used includes a fixing bolt 12 for fixing the upper and lower flanges 3a, 3b provided at the upper and lower ends of the cylindrical body 3 to the top plate 4 and the bottom plate 5, and a fixing nut 13 screwed into the fixing bolt 12. It is characterized by comprising.

  The method for reclaiming foundry sand according to claim 11 is the method for reclaiming foundry sand according to claim 10, wherein a fixing bolt 12 that is a fixing tool 11 for fixing the bottom plate 5 to the lower end portion of the cylindrical main body 3 is fixed. Of the nut 13, the head 12 a of the fixing bolt 12 is positioned on the back side of the bottom plate 5, and the head 12 a forms a leg portion 15 with respect to the installation surface 14 on which the combustion heat-resistant container 1 is installed (FIG. 6). Reference) is characterized in that a gap 16 for discharging the heated gas A discharged from the bottom plate 5 is formed between the heat-resistant container 1 and the installation surface 14 by the leg portion 15.

  The effect of the invention by the above solution will be described with reference numerals of the embodiments described later. According to the casting sand recycling method of the invention according to claim 1, the used shape retaining resin P is attached. The casting sand SP is accommodated in the heat-resistant container 1 for combustion, and the heated gas A is press-fitted into the heat-resistant container 1, and the shape-retaining resin P is combusted by the heated gas A thus injected, and FIG. As shown, the combustion part B of the shape-retaining resin P sequentially moves from the upper side of the heat-resistant container 1 to the lower part, and the combustion part B reaches the lower end part of the heat-resistant container 1, whereby the foundry sand The shape-retaining resin P is burned and removed from the SP, and the pressurized gas A is discharged from the bottom of the heat-resistant container 1 to the outside air, and the shape-retaining resin P is removed in the heat-resistant container 1. Since the casting sand S remains, it has a small combustion resistance. The container 1 can remove the shape-retaining resin P from the used foundry sand SP to which the shape-retaining resin P is adhered, so that a high-quality reusable foundry sand S can be regenerated. Therefore, even if a small amount of used foundry sand generated in the factory is used, it is possible to regenerate good quality foundry sand at a low cost.

  Moreover, since the regenerating work can be performed by the small combustion heat-resistant container 1 that can be installed on a work table used in a factory, it is extremely practical, economical, and easy to handle.

  In particular, in the present invention, the heated gas A is pressed into the heat-resistant container 1 in a sealed state with respect to the used foundry sand SP to which the shape-retaining resin P accommodated in the heat-resistant container 1 is attached. It is characterized in that the heated gas A is applied to the foundry sand SP and immediately burned to a high temperature. For example, it is conceivable that the foundry sand is burned by the heat of a flame such as a burner while being open to the outside of the foundry sand, but the burning operation is performed on the foundry sand with a flame such as a burner in the open air. Then, a part of the combustion heat is released to the outside air, and the combustion efficiency is deteriorated. On the other hand, in the present invention, the heated gas A is press-fitted into the heat-resistant container 1 in a sealed state, and the foundry sand. Since the heated gas A is applied to the SP and immediately burned to a high temperature, the heated gas A that is press-fitted into the heat-resistant container 1 efficiently contributes to the combustion of the foundry sand SP. The molding sand SP to which the heated gas A is applied can be burned and removed in a short time because the shape-retaining resin P is immediately burned to a high temperature.

Furthermore, due to the combustion action of the heated gas A, the shape-retaining resin is burned as a combustion gas heated to a high temperature of about 1200 ° C. as a result of the experiment by the oxidation reaction, and decomposed into CO ₂ and H ₂ O. It is released into the atmosphere and is environmentally friendly.

  According to the second aspect, the applicant of the present invention has, as a result of various experiments, the heated gas generator 2 for generating the heated gas as it is, which has been conventionally used as a superheated steam generator for generating superheated steam. As a result, the heated gas generating device 2 can be manufactured at a relatively low cost, and as a result, the used casting sand SP is attached to this at a low cost. The shape-retaining resin P can be burned and removed.

  According to the third aspect, the outlet temperature of the heated gas generated from the heated gas generator 2 is 650 ° C. to 850 ° C. as a result of various experiments. If the temperature is 650 ° C. or lower, as a result of the experiment, even if the heated gas is press-fitted into the combustion heat-resistant container 1, a portion that does not completely burn the shape-retaining resin P adhering to the used foundry sand SP is generated. Turned out to be. Further, if the outlet temperature of the heated gas from the heated gas generating device 2 is 850 ° C. or higher, the energy cost for operating the heated gas generating device 2 will be burdened more than necessary, and the heated gas is generated. The cost becomes expensive and is not practical.

  According to the fourth aspect, the press-in temperature of the heated gas generated by the heated gas generating device 2 and blown into the heat-resistant container 1 from the device is 350 ° C. to 850 ° C. If the temperature is 350 ° C. or lower, as a result of the experiment, even if the heated gas is press-fitted into the combustion heat-resistant container 1, a portion that does not completely burn the shape-retaining resin P adhering to the used foundry sand SP is generated. Turned out to be. Moreover, if it becomes 850 degreeC or more, the energy cost for operating the heating gas production | generation apparatus 2 will be burdened more than needed similarly to Claim 3, and the cost for producing | generating heating gas will become expensive. It is not practical.

  According to claim 5, the press-fitting pressure of the heated gas generated by the heated gas generating device 2 and press-fitted from the device into the heat-resistant container 1 for combustion needs to be higher than the atmospheric pressure of 0.1 MPa. As a result of the experiment, at 0.2 MPa, even if the heated gas is press-fitted into the heat-resistant combustion container 1, sufficient combustion work cannot be performed, and 0.3 MPa or more is necessary, and 0.6 MPa It has been found that the above press-fitting pressure is not necessary.

  According to the method for reclaiming foundry sand of the invention according to claim 6, the heat-resistant container 1 for combustion used in this is composed of the cylindrical main body 3 in which the used foundry sand SP is accommodated, and the cylindrical main body 3 The top plate 4 is detachably fixed to the upper end portion and the bottom plate 5 is detachably fixed to the lower end portion of the cylindrical main body 3. The heating gas A is put into the heat-resistant container 1 on the top plate 4. A pressure inlet 6 for press-fitting is provided, and the bottom plate 5 is provided with a heated gas discharge hole 7 for discharging only the heated gas A (including combustion exhaust) press-fitted into the heat-resistant container 1 into the atmosphere. Because it consists of a very simple structure, it can be manufactured at low cost. Moreover, since the cylindrical main body 3, the top plate 4, and the bottom plate 5 can be disassembled, even if they are damaged by a harsh operation such as a long-term combustion operation, the result is obtained by replacing each disassembled part. Can be used for a long time.

  According to the method for reclaiming foundry sand according to the seventh aspect of the present invention, the substantially circular dish-shaped partition frame 8 is fixed to the lower surface of the top plate 4 of the heat-resistant container 1 for combustion used in this, and the top plate 4 and the partition are separated. A relay chamber 9 for the heated gas A is formed surrounded by the frame 8. A plurality of the heated gases A are provided in the partition frame 8 from the pressure inlet 6 provided in the top plate 4 via the relay chamber 9. Therefore, the heated gas A that has been press-fitted into the combustion heat-resistant container 1 is once dispersed throughout the interior of the relay chamber 9 and dispersed. Since the heated gas A is press-fitted into the heat-resistant container 1 from a plurality of press-fitting holes 10 provided in the partition frame 8, the heated gas A is not biased with respect to the foundry sand PS in the combustion heat-resistant container 1. The combustion operation can be performed uniformly over the entire area.

  According to the casting sand recycling method of the invention according to claim 8, a plurality of the press-fitting holes 10 provided in the partition frame 8 are provided near the inner wall of the cylindrical main body 3 at appropriate intervals in the circumferential direction. Therefore, when the used foundry sand SP accommodated in the cylindrical main body 3 is heated by the heated gas A, the portion of the foundry sand SP in contact with the cylindrical main body 3 is heated on the outer wall of the cylindrical main body 3. However, the heating gas A that is press-fitted into the cylindrical main body 3 has a plurality of press-fitting holes 10 at appropriate intervals in the circumferential direction near the inner wall of the cylindrical main body 3 of the relay chamber 9. Since it is provided, first, the heated gas A comes into contact with the portion of the foundry sand SP filled near the inner wall of the cylindrical main body 3, burns from this portion, and propagates the combustion heat from that portion to the central portion. The casting sand SP is burned uniformly over the entire area. Will be exerted to use, the shape-retaining resin P adhered to the molding sand SP can be efficiently burned and removed.

  According to the method for reclaiming foundry sand according to the ninth aspect of the present invention, the heated gas discharge hole 7 provided in the bottom plate 5 allows passage of the heated gas A (including combustion exhaust) but does not allow the foundry sand S to pass. Since it consists of innumerable heated gas discharge pores 7a provided in a scattered manner over the entire area of the bottom plate 5 so as to prevent it, the air flows from the infinite number of heated gas discharge pores 7a provided in a scattered manner over the entire area of the bottom plate 5. The heated gas A released to the sand is evenly in contact with the entire area of the foundry sand SP and burns reliably without causing unburned portions in the shape-retaining resin P adhering to the foundry sand SP. The sand S can be manufactured so as to remain in the heat-resistant container 1.

  According to the casting sand recycling method of the invention according to claim 10, the fixture 11 to which the top plate 4 and the bottom plate 5 are fixed to the upper and lower end portions of the cylindrical main body 3 is provided at the upper and lower end portions of the cylindrical main body 3. Since the provided upper and lower flanges 3a and 3b are composed of a fixing bolt 12 for fixing the upper and lower flanges 3a and 3b over the top plate 4 and the bottom plate 5 and a fixing nut 13 screwed into the fixing bolt 12, the structure of the fixing means is simple and the fixing operation is easy. Can be done.

  According to the casting sand recycling method of the invention according to claim 11, the head of the fixing bolt 12 among the fixing bolt 12 and the fixing nut 13 as the fixing tool 11 that fixes the bottom plate 5 to the lower end portion of the cylindrical main body 3. 12a is located on the back side of the bottom plate 5, and the head portion 12a forms a leg 15 for the installation surface 14 on which the combustion heat-resistant container 1 is installed, and the leg 15 provides the heat-resistant container 1 and the installation surface 14 to each other. A gap 16 for discharging the heated gas A discharged from the bottom plate 5 is formed between the fixing bolt 12 and the fixing nut 13. The fixing bolt 12 and the fixing nut 13 are used to fix the cylindrical body 3 to the top plate 4 and the bottom plate 5. Among them, the head 12a of the fixing bolt 12 attached so as to be located on the back surface side of the bottom plate 5 is provided with a clearance 16 for discharging the heated gas A discharged from the bottom plate 5 as the leg portion 15. Can play a role For this reason, the heating gas A can be smoothly discharged from the bottom plate 5 of the heat-resistant container 1 through the discharge gap 16 to the atmosphere without any special work simply by installing the heat-resistant container 1 on the installation surface 14. Can do.

It is explanatory drawing which shows one Embodiment of the molding sand reproduction | regeneration apparatus for enforcing the reproduction method of the molding sand which concerns on this invention. It is a front view which shows the use condition of the heat-resistant container for combustion which is the principal part of a foundry sand reproduction | regeneration apparatus. It is a disassembled perspective view of the heat-resistant container for combustion. It is the perspective view seen from the back surface side of the top plate which is a component of the heat-resistant container for combustion. It is a top view of the baseplate which is a component of the heat-resistant container for combustion. The internal structure of the heat-resistant container for combustion is shown, the used foundry sand is accommodated in the heat-resistant container, and it is a sectional front view showing the use state. It is explanatory drawing which shows typically the state which measures the time-dependent change of the combustion state of the used foundry sand in the heat-resistant container for combustion. It is a graph which shows a time-dependent change in the thermal container of the foundry sand shown in FIG.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a preferred embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a foundry sand recycling apparatus 17 for performing a casting sand recycling method according to the present invention. This foundry sand recycling apparatus 17 is used for combustion in order to burn and remove the shape-retaining resin P adhering to the used foundry sand SP housed in the heat-resistant container 1 for combustion which is the main part of the present invention. A heated gas generator 2 that generates the heated gas A in order to press-fit the high-temperature heated gas A into the heat-resistant container 1, and a compressed gas supply device that supplies compressed gas (compressed air) to the heated gas generator 2 18 (air compressor) and a heated gas supply piping section piped in order to press-fit the heated gas generated by the heated gas generating device 2 into the heat-resistant combustion container 1 containing the used foundry sand SP. 19.

  The heated gas generating device 2 is composed of a high frequency induction heating device. The heating coil that is a heating element is induction-heated from the high frequency power supply device, and the compressed gas is heated by passing the compressed gas through the heating coil. It is produced, can be heated efficiently with high power density, and is clean and environmentally effective because it does not use fossil energy. The heated gas generator 2 is not limited to a high-frequency induction heater, and may be a device that allows compressed gas to pass through a known high-performance heater group such as a sheathed heater. In FIG. 1, V1 and V2 indicate open / close operation valves.

Molding sand S, the silica sand (S _i O ₂ is the main component) is formed by a shape-retaining resin on the surface of the sand particles consisting of such (a binder, such as phenol resin coated resin-coated sand (RCS), Further, the surface of the casting sand S is coated with the same shape-retaining resin such as phenolic resin, and the shape-retaining resin enhances the bonding force between the sand particles and the sand particles, and the shape retaining force of the entire sand core 1 is increased. As the shape-retaining resin P, in addition to the phenolic resin, a furan resin or a urethane resin is used.

  Next, the process of burning and removing the shape-retaining resin P accommodated in the combustion heat-resistant container 1 using the foundry sand recycling apparatus 17 as shown in FIG. 1 will be described.

  When the used foundry sand SP taken out from the mold is formed in the shape of the mold, it is crushed into an appropriate size and accommodated in the heat-resistant container 1 for combustion. At this time, the on-off operation valves V1 and V2 shown in FIG. 1 are closed. Then, the open / close operation valves V1 and V2 are opened, the compressed gas supply device 18 (air compressor) and the heated gas generator 2 (high frequency induction heating device, sheathed heater heating device, etc.) are operated to generate heated gas, The operation of press-fitting this heated gas into the combustion heat-resistant container 1 from the tip end of the heated gas supply pipe section 19 is started. At this time, the pressure of the heated gas guided into the heated gas supply pipe section 19 and press-fitted into the heat-resistant combustion container 1 is higher than the atmospheric pressure (0.1 MPa), and 0.2 MPa is insufficient. The pressure of 0.3 MPa is required, the outlet temperature of the heated gas generated by the heated gas generator 2 is 780 ° C., and the pressure of the heated gas injected into the combustion heat-resistant container 1 is 400 ° C.

When the high-temperature gas S composed of a heated gas having a pressure and temperature as described above is pressed into the combustion heat-resistant container 1 at a pressure of 0.3 MPa for 5 minutes, for example, the shape-retaining resin adhered to the used foundry sand SP there example phenolic resins combust gasified by touching the oxygen in the hot gas S, a compound with oxygen, complete combustion to CO ₂ and H by combustion gas of a high temperature of about 1200 ° C. before and after results of the experiment It decomposes into ₂ O and is released into the atmosphere from the heated gas discharge hole 7 of the bottom plate 5. For example, the combustion gas having a maximum value of 850 ° C., specifically about 400 ° C., is blown into the used foundry sand SP mixed with 2.5% by weight of phenolic resin by pressure. The temperature rises to 1200 ° C., the phenol resin is almost completely burned, and the gross value indicating the residual ratio of the shape-retaining resin (phenolic resin) remaining in the foundry sand SP (the lower the amount of remaining resin in the foundry sand SP is, the lower the amount is) The cast value is a value obtained by completely removing -0.07%. In another example, the casting sand SP is mixed with a phenolic resin having a weight ratio of 2.7%. The figure shows that the gross value of the phenolic resin, 0.04%, was almost completely removed by blowing the mixed combustion gas under the same conditions. Thus, the shape-retaining resin P is completely burned and removed from the foundry sand SP, and no resin component remains, so that it can be reused as fresh sand. Further, since CO ₂ and H ₂ O released into the atmosphere are harmless, they are friendly to the environment.

  Therefore, as shown in FIG. 1, the hot gas S made of the heated gas having the above-described characteristics is applied to the foundry sand SP accommodated in the heat-resistant container 1 for combustion from above. .3 MPa, the outlet temperature from the heated gas generator 2 is 780 ° C., and the press-fitting temperature into the heat-resistant container 1 for combustion is about 400 ° C., for example, for 5 minutes, the foundry sand SP has a high temperature of about 1200 ° C., for example. The temperature of the combustion gas is increased, whereby the shape-retaining resin P in the foundry sand SP is completely burned and vaporized, and is removed and discharged from the foundry sand SP.

  In carrying out the above-described method for reclaiming the foundry sand according to the present invention, the temperature of the heated gas may be any temperature at which the shape retention resin P of the foundry sand SP can be combusted when the heated gas is pressed into the foundry sand SP. Preferably, it is set to 350 ° C. to 850 °. The exit temperature from the heated gas generator 2 at this time is set to 650 ° C to 850 ° C. Further, the pressure of the heated gas is higher than the atmospheric pressure of 0.1 MPa, and 0.2 MPa is insufficient, and for example, a range of 0.3 to 0.6 MPa is preferable.

  FIG. 2 shows a use state of the combustion heat-resistant container 1 which is a main part of the present invention. The combustion heat-resistant container 1 includes a cylindrical main body 3, a top plate 4 and a bottom plate 5. The bottom plate 5 is detachably fixed to the cylindrical main body 3 by a fixture 11.

  The combustion heat-resistant container 1 is installed on a work table 21 that forms the installation surface 14, and the work table 21 is supported by a lift cylinder 22 and a guide rod 23 provided on a machine base 21 a and can be lifted and lowered. As indicated by the phantom lines, the combustion heat-resistant container 1 is brought close to the heated gas supply pipe portion 19 supported by the support frame 19a by the lifting cylinder 22 via the work table 21, and from the male screw portion 24a and the female screw portion 24b. Both are connected by the connecting tool 24, and the heated gas A fed from the heated gas supply pipe section 19 is press-fitted into the heat resistant container 1 for combustion. During the press-fitting work of the heated gas A, both are in a connected state, and when the heating work is finished, the connecting tool 24 is released and lowered to a lower position indicated by a solid line.

  3 and 4 are exploded perspective views of the combustion heat-resistant container 1, which is a main part of the present invention. The upper and lower ends of the cylindrical main body 3 are provided with an upper flange 3a and a lower flange 3b. The upper flange 3a and the top plate 4 of the cylindrical body 3 are screwed by fixing bolts 12 and fixing nuts 13 as fixing tools 11 by fixing holes 25 and 25 provided in both of them, and the lower flange 3b of the cylindrical main body 3 and The bottom plate 5 is also screwed by the fixing bolt 12 and the fixing nut 13 through fixing holes 26 and 26 provided in both of them. The thickness of the cylindrical main body 3 is 14 mm, the thickness of the upper and lower flanges 3 a and 3 b of the cylindrical main body 3 is 24 mm, and the protruding amount from the cylindrical main body 3 is 60 mm. The top plate 4 and the bottom plate 5 have outer diameters of 400 mm, the top plate 4 has a thickness of 15 mm, and the bottom plate 5 has a thickness of 3.2 mm. Furthermore, the inner diameter of the cylindrical main body 3 is 254 mm, and the outer diameters of the top plate 4 and the bottom plate 5 are 400 mm. These are formed of a metal heat-resistant material such as a steel plate. Of course, these dimensions and materials are merely examples, but as can be seen from these dimensions, the heat-resistant container 1 for combustion is characterized by being made quite compact. In addition to the metal material such as a steel plate, the material may be a metal material with a known refractory material lined.

  A press-fit socket 27 for press-fitting the heated gas A into the combustion heat-resistant container 1 is provided at the center of the top plate 4 so as to communicate with the upper surface of the pressure inlet 6. As shown in FIG. 2, the screw is attached to the male threaded portion 24a of the connector 24 by screwing or welding. Further, as shown in FIG. 4, a substantially circular dish-shaped partition frame 8 is fixed to the lower surface of the top plate 4 by welding, and the heated gas A is burned near the outer periphery of the partition frame 8 at appropriate intervals in the circumferential direction. A plurality of press-fitting holes 10 for press-fitting into the heat-resistant container 1 are provided.

  As shown in FIG. 3 or 5, the bottom plate 5 is provided with a heated gas discharge hole 7 for releasing the heated gas A press-fitted into the combustion heat-resistant container 1 into the atmosphere. The heated gas discharge hole 7 is composed of innumerable heated gas discharge holes 7a provided over the entire area of the bottom plate 5 so as to allow the heated gas A to pass but prevent the foundry sand S from passing therethrough. As can be seen from the state shown in FIG. 3 or FIG. 5, the heated gas discharge pores 7 a are formed in a dotted manner from the center of the bottom plate 5 in the form of heating gas discharge pores 7 a. Each pore of the gas discharge pore 7a consists of a minimal hole of 0.2 to 0.3 mm. In order to form this very small hole 7a in the bottom plate 5 made of a steel plate, the thickness of the bottom plate 5 is 2.5 mm to 4 mm, preferably 3.2 mm, as a result of experiments. Thereby, the passage of the heated gas A is allowed, but the passage of the foundry sand S is prevented.

  As described above, according to the method for reclaiming foundry sand according to the present invention, the used foundry sand SP to which the shape-retaining resin P is adhered is accommodated in the heat-resistant container 1 for combustion, The heated gas A is press-fitted, and the shape-retaining resin P is combusted by the press-fitted heated gas A, and the combustion part B is sequentially moved from the upper side to the lower side of the heat-resistant container 1 as shown in FIG. As the combustion part B reaches the lower end of the heat-resistant container 1, the shape-retaining resin P is burned and removed from the foundry sand SP, and the heated gas A flows from the bottom of the heat-resistant container 1. Since the foundry sand S from which the shape-retaining resin P has been removed remains in the heat-resistant container 1 as it is released to the outside air, as shown in the above example, it is a very compact and small-sized combustion chamber. Used with shape-retaining resin P attached by heat-resistant container 1 The shape-retaining resin P can be removed from the foundry sand SP, which makes it possible to regenerate the high-quality reusable foundry sand S, and the amount of used foundry sand generated in the factory is small. However, good-quality foundry sand can be regenerated at low cost.

  Moreover, as shown in FIG. 2, the upper surface of the work table 21 used in the factory is used as the installation surface 14, and the regeneration work can be performed by the small heat-resistant container 1 that can be installed on the installation surface 14. And economical, and easy to handle.

  In particular, in the present invention, the heated gas A is pressed into the heat-resistant container 1 in a sealed state with respect to the used foundry sand SP to which the shape-retaining resin P accommodated in the heat-resistant container 1 is attached. It is characterized in that the heated gas A is applied to the foundry sand SP and immediately burned to a high temperature. For example, it is conceivable that the foundry sand is burned by the heat of a flame such as a burner while being opened to the atmosphere, but the burning operation is performed on the foundry sand with a flame such as a burner in an open state. Then, a part of the combustion heat is released to the atmosphere, and the combustion efficiency is deteriorated. On the other hand, in the present invention, the heated gas A is press-fitted into the heat-resistant container 1 in a sealed state, and the foundry sand. Since the heated gas A is applied to the SP and immediately burned to a high temperature, the heated gas A press-fitted into the heat-resistant container 1 contributes efficiently to the combustion of the foundry sand SP. The molding sand SP to which the heated gas A is applied can be burned and removed in a short time because the shape-retaining resin P is immediately burned to a high temperature.

  The combustion heat-resistant container 1 includes a cylindrical main body 3 in which used foundry sand SP is housed, a top plate 4 that is detachably fixed to an upper end portion of the cylindrical main body 3, and the cylindrical main body. 3 is provided with a bottom plate 5 that is detachably fixed to the lower end of the plate 3. The top plate 4 is provided with a pressure inlet 6 for press-fitting the heated gas A into the heat-resistant container 1, and the bottom plate 5 has the heat-resistant container. Since the heating gas discharge hole 7 that discharges only the heating gas A press-fitted into the atmosphere 1 is provided in the atmosphere, it can be manufactured at low cost. Moreover, since the cylindrical main body 3, the top plate 4, and the bottom plate 5 can be disassembled, even if they are damaged by a harsh operation such as a long-term combustion operation, the result is obtained by replacing each disassembled part. Can be used for a long time.

  Further, as described above, a substantially circular dish-shaped partition frame 8 is fixed to the lower surface of the top plate 4 of the combustion heat-resistant container 1 and is surrounded by the top plate 4 and the partition frame 8, as shown in FIG. Is formed in the partition frame 8 from the pressure inlet 6 provided in the top plate 4 via the relay chamber 9 as shown by an arrow a. Since the plurality of press-fitting holes 10 are press-fitted into the heat-resistant container 1, the heated gas A press-fitted into the combustion heat-resistant container 1 is once dispersed throughout the interior of the relay chamber 9 and dispersed. Since the heated gas A is pressed into the heat-resistant container 1 from the plurality of press-fitting holes 10 provided in the partition frame 8, the heated gas A is not biased with respect to the foundry sand PS in the combustion heat-resistant container 1. The combustion operation can be performed uniformly over the entire area.

  Furthermore, as shown in FIG. 4 or FIG. 6, a plurality of the press-fitting holes 10 provided in the partition frame 8 are provided at appropriate intervals in the circumferential direction so as to be along the inner wall near the inner wall of the cylindrical body 3. Therefore, when the used foundry sand SP accommodated in the cylindrical main body 3 is heated by the heated gas A, the portion of the foundry sand SP in contact with the cylindrical main body 3 is the same as that of the cylindrical main body 3. Although the outer wall is deprived of heat and the heating efficiency tends to be poor, the heated gas A that is press-fitted into the cylindrical main body 3 is close to the inner wall of the cylindrical main body 3 of the relay chamber 9 at the appropriate intervals in the circumferential direction. First, the heated gas A comes into contact with the portion of the casting sand SP filled near the inner wall of the cylindrical main body 3 and burns from this portion, and the heat of combustion from that portion to the center portion. By spreading the casting sand SP over the entire area It will be exerted combustion action, the shape-retaining resin P adhered to the molding sand SP can be efficiently burned and removed.

  Further, as described above, the heated gas discharge holes 7 provided in the bottom plate 5 are provided in a dotted manner over the entire area of the bottom plate 5 so as to permit the passage of the heated gas A but prevent the passage of the foundry sand S. Since the innumerable heated gas discharge pores 7a are formed, the heated gas A released into the atmosphere from the innumerable heated gas discharge pores 7a provided in a dotted manner over the entire area of the bottom plate 5 is in uniform contact with the entire area of the casting sand SP. In addition, the shape-retaining resin P adhering to the foundry sand SP can be reliably burned without causing an unburned portion, so that the high-quality reclaimed foundry sand S remains in the heat-resistant container 1. .

  Furthermore, the fixture 11 to which the top plate 4 and the bottom plate 5 are fixed to the upper and lower ends of the cylindrical main body 3 is provided with upper and lower flanges 3a and 3b provided on the upper and lower ends of the cylindrical main body 3 and the top plate 4 and Since the fixing bolt 12 is fixed to the bottom plate 5 and the fixing nut 13 is screwed into the fixing bolt 12, the structure of the fixing means is simple and the fixing operation can be easily performed. The fixture 11 is not limited to the bolt-nut structure fixture 11, and may be, for example, a clamp-type fixture including a U-shaped clamp body, a clamp piece, a clamp bolt, and the like. Of course, any fixture having a known structure that can fix the flange pieces together may be used.

  As shown in FIG. 6, the heated gas A press-fitted into the connected combustion heat-resistant container 1 from the press-fit socket 27 through the fitting 24 into the heated gas supply pipe section 19 through the connector 24 is contained in the partition frame 8. The used foundry sand SP that is press-fitted into the combustion heat-resistant container 1 through the plurality of press-fitting holes 10 from the relay chamber 9 and crushed into blocks or granules into an appropriate size in the combustion heat-resistant container 1 is obtained. The upper surface portion is ignited and combusted, the combustion portion moves from the upper end portion to the lowermost end portion, and the heated gas A after the combustion operation is completed as shown in FIG. The heated gas discharge pores 7a are released into the outside air. At this time, the fixing bolt 12 and the fixing nut 13 which are the fixing tools 11 for fixing the bottom plate 5 to the lower end portion of the cylindrical main body 3 are fixed. The head 12a of the bolt 12 is located on the back side of the bottom plate 5, The part 12a forms a leg portion 15 for the installation surface 14 on which the combustion heat-resistant container 1 is installed, and the heated gas released from the bottom plate 5 between the heat-resistant container 1 and the installation surface 14 by the leg portion 15. Since the A release gap 16 is formed, the fixing bolt 12 and the fixing nut 13 serve as a fixture for the cylindrical main body 3, the top plate 4 and the bottom plate 5, and of these, the back side of the bottom plate 5 The head 12a of the fixing bolt 12 attached so as to be positioned at can serve as a leg 15 to provide a discharge gap 16 for the heated gas A released from the bottom plate 5, and the heated gas A is indicated by an arrow b. As shown in the figure, the heating gas A can be smoothly discharged from the bottom plate 5 of the heat-resistant container 1 through the discharge gap 16 without any special work simply by installing the heat-resistant container 1 on the installation surface 14. Can .

  In the present invention, as shown in FIG. 7, the heated gas A is press-fitted into the combustion heat-resistant container 1 as indicated by an arrow a, and the shape-retaining resin P is burned by the injected heated gas A, and The combustion section B sequentially moves from the upper side BA to the lower side of the heat-resistant container 1 as BB and BC, and when the combustion part B reaches the lower end BC of the heat-resistant container 1, the shape retention from the foundry sand SP. In order to measure the temporal change in the combustion state of the combustion parts BA, BB and BC, as shown in FIG. A small hole is provided, and as shown in the figure, temperature sensors S1 to S3 made of a thermocouple are inserted into the center of the foundry sand S at the tip of the thermocouple, and S1 is inserted from the press-fitting hole 10 of the partition frame 8 to a1. Measure the temperature of the foundry sand S at the position BA of 20mm as shown in A temperature sensor to be. S2 is a temperature sensor that measures the temperature of the foundry sand SP at a position BB of 100 mm as indicated by a2 from the press-fitting hole 10 of the partition frame 8. S3 is a temperature sensor that measures the temperature of the foundry sand S at a position C of 200 mm as indicated by a3 from the press-fitting hole 10 of the partition frame 8.

  FIG. 8 is a line graph showing the time course of temperature at the measurement positions BA to BC when removing the molding sand S burned with the shape-retaining resin P from the heat-resistant container 1 for combustion. Among them, the broken line indicated by the solid line BA indicates the temporal temperature course at the measurement position BA, the broken line indicated by the one-dot chain line BB indicates the temporal temperature course at the measurement position BB, and the broken line indicated by the two-dot chain line BC indicates the measurement position. It is a locus | trajectory which shows the time-temperature course in BC, respectively.

Referring to the graph of FIG. 8, when the temporal temperature of the foundry sand S is seen, the measurement position of 20 mm from the press-fitting hole 10 of the partition frame 8 is about 20 seconds after the heated gas A is press-fitted into the heat-resistant combustion container 1. Burns to phenolic resin P of foundry sand SP with BA, rapidly rises to around 1200 ° C, becomes high temperature during combustion, decreases in temperature at the end of combustion, and heat resistance for combustion by the flow of heated gas at about 400 ° C It can be assumed that the combustion in the container 1 continuously propagates in the direction of the tip. That is, by this combustion, the phenolic resin is decomposed into CO ₂ and H ₂ O, and when the combustion is finished, the foundry sand S descends to about 400 ° C. and moves to the bottom plate 5 side of the combustion heat-resistant container 1. I understand that

  Further, the temperature at the measurement position BB where the foundry sand SP is 100 mm from the press-fitting hole 10 of the partition frame 8 is about 1 minute 14 seconds after the hot gas (heated gas) is press-fitted into the foundry sand SP. Like the measurement position BA, the phenolic resin is ignited and burned, and it is understood that the temperature has dropped when the combustion is finished. Further, the temperature at the measurement position BC where the foundry sand SP is 200 mm from the press-fitting hole 10 of the front partition frame 8 is also 1200 ° C. after about 2 minutes and 52 seconds have passed since the hot gas (heated gas) is pressed into the foundry sand SP. Like the measurement positions BA and BB, the phenolic resin is ignited and burned, and it can be read that the temperature has dropped when the combustion is finished.

  As described above, when combustion removal of the shape-retaining resin P from the used foundry sand SP in the combustion heat-resistant container 1 is completed, as shown in FIG. 24 is released, the combustion heat-resistant container 1 is lowered to a position where the work can be easily performed by the elevating cylinder 22, the fixture 11 is released at that position, the top plate 4 is removed from the cylindrical body 3, and if necessary By removing the cylindrical main body 3 from the bottom plate 5 and lifting the cylindrical main body 3 upward, the reclaimed foundry sand S inside the cylindrical main body 3 can be easily taken out.

P Shape-retaining resin SP Used casting sand S Casting sand from which shape-retaining resin has been removed A Heated gas 1 Combustion heat-resistant container 2 Heated gas generator 3 Tubular body 3a Upper flange 3b Lower flange 4 Top plate 5 Bottom plate 6 Pressure inlet 7 Heated gas discharge hole 7a Heated gas discharge hole 8 Partition frame 9 Relay chamber 10 Press-in hole 11 Fixing tool 12 Fixing bolt 12a Fixing bolt head 13 Fixing nut 14 Installation surface 15 Leg 16 Release gap 17 Casting Sand recycling equipment

Claims (11)

  The used foundry sand to which the shape-retaining resin is adhered is accommodated in the heat-resistant container for combustion, and a heated gas is injected into the heat-resistant container, and the shape-retaining resin is burned by the injected heated gas. The shape-retaining resin combustion part sequentially moves from the upper side to the lower side of the heat-resistant container, and the combustion part reaches the lower end of the heat-resistant container, whereby the shape-retaining resin burns from the foundry sand. Casting sand regeneration, wherein the heated gas is released from the bottom of the heat-resistant container, and the molding sand from which the shape-retaining resin is removed remains in the heat-resistant container. Method.   2. The method for reclaiming foundry sand according to claim 1, wherein the heated gas is generated by a heated gas generator into which compressed gas is introduced.   The method for reclaiming foundry sand according to claim 2, wherein the outlet temperature of the heated gas generated by the heated gas generator is 650 ° C to 850 ° C.   The foundry sand according to claim 2 or 3, wherein the pressure of the heated gas generated by the heated gas generating device and press-fitted into the combustion heat-resistant container from the device is 350 ° C to 850 ° C. How to play.   The press-fitting pressure of the heated gas generated by the heated gas generating device and press-fitted from the device into the combustion heat-resistant container is 0.3 MPa to 0.6 MPa. A method for reclaiming foundry sand described in 1.   The heat-resistant container for combustion is detachable from a cylindrical main body in which used foundry sand is accommodated, a top plate removably fixed to the upper end of the cylindrical main body, and a lower end of the cylindrical main body. The top plate is provided with a pressure inlet for pressurizing the heated gas into the heat-resistant container, and the bottom plate has only the heated gas press-fitted into the heat-resistant container into the atmosphere. The method for reclaiming foundry sand according to any one of claims 1 to 5, wherein a heated gas discharge hole is provided.   A substantially circular dish-shaped partition frame is fixed to the lower surface of the top plate and is surrounded by the top plate and the partition frame to form a heating gas relay chamber, and the heating gas is supplied from a pressure inlet provided on the top plate to the relay chamber. The method for reclaiming foundry sand according to claim 6, wherein the sand is press-fitted into the heat-resistant container through a plurality of press-fitting holes provided in the partition frame.   The method for reclaiming foundry sand according to claim 7, wherein a plurality of the press-fitting holes provided in the partition frame are provided at appropriate intervals in the circumferential direction near the inner wall of the cylindrical main body.   The heated gas discharge hole provided in the bottom plate is composed of innumerable heated gas discharge pores provided in a dotted manner over the entire area of the bottom plate so as to allow the passage of the heated gas but prevent the passage of the foundry sand. The method for reclaiming foundry sand according to any one of claims 6 to 8.   The fixture for fixing the top and bottom plates to the upper and lower ends of the cylindrical body includes a fixing bolt for fixing the upper and lower flanges provided on the upper and lower ends of the cylindrical body across the top and bottom plates, and the fixing bolt. The method for reclaiming foundry sand according to any one of claims 6 to 9, comprising a fixing nut screwed into the sand.   Of the fixing bolts and fixing nuts that fix the bottom plate to the lower end of the cylindrical main body, the head of the fixing bolt is located on the back side of the bottom plate, and the head is installed with the heat-resistant container for combustion. The leg part with respect to an installation surface is formed, The clearance gap for the heating gas discharge | released from the said baseplate is formed between the said heat-resistant container and the installation surface by this leg part, The Claim 10 characterized by the above-mentioned. Method of reclaiming foundry sand.

Images