JP2017131908A - Heater of casting sand - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heater of casting sand capable of uniformly heating the casting sand, by agitating the whole of a casting of a storage tank.SOLUTION: A heater comprises a gas supply device 201 for supplying heating gas so as to blow the heating gas upward into a storage tank 10 and a convection cylinder 202 arranged in the storage tank 10 in a position for blowing the heating gas into a cylinder from a lower end opening part. An upper end opening part of the convection cylinder 202 is formed as an overflow port 203 for blowing out casting sand in the convection cylinder 202 blown up by the heating gas blown into the convection cylinder 202 to the outside of the convection cylinder 202 in the storage tank 10, and a sand inflow hole 204 for making the casting sand outside of the convection cylinder 202 flow in the convection cylinder 202, is formed on a side surface of the convection cylinder 202. While largely agitating by convecting the casting sand between the inside and the outside of the convection cylinder 202, the casting sand can be heated by heated air.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an apparatus for heating foundry sand such as a binder coated sand used in the production of a casting mold.

  Casting molds are manufactured by molding foundry sand. For example, in the shell mold method, a binder coated sand in which the surface of a refractory aggregate such as silica sand is coated with a solid binder made of a thermosetting resin such as a phenol resin is used as foundry sand, and is then applied to a heated mold. A mold can be produced by filling the binder coated and baking the binder coated sand in a mold.

  Thus, when manufacturing a casting mold using casting sand, it is common to store casting sand in a storage tank such as a hopper and to supply the casting mold to a mold for mold manufacturing. . And when storing molding sand in a storage tank in this way, it has been conventionally performed to preheat the molding sand in the storage tank.

  That is, when the temperature is low, such as in winter, the temperature of the foundry sand in the storage tank is also lowered. Therefore, when the foundry sand is filled in a heated mold and molded, the molding time becomes longer. In particular, when the binder-coated sand is used as foundry sand as in the shell mold method, if the temperature of the binder-coated sand is low, the time for curing the binder becomes long, and the production efficiency of the mold becomes low. . Therefore, it is desirable to preheat the foundry sand in the storage tank to prevent a decrease in the temperature of the foundry sand. Even when the temperature is high, such as in summer, if the foundry sand is heated to a temperature at which the binder does not harden, the time for producing the mold can be shortened. It is desirable to preheat the foundry sand in the tank.

  Various heating devices for preheating the foundry sand in the storage tank have been proposed in the past.A heat exchanger that allows the heat medium to pass through is placed in the storage tank, or a heating jacket is provided in the storage tank. It is common to provide it. However, in this case, since the foundry sand is heated by heat transfer from the heat exchanger or the jacket, the efficiency of heating the foundry sand is low, and the portion of the foundry sand that is in contact with the heat exchanger or the jacket is The heating temperature is different from the part of the foundry sand away from the heat exchanger and the jacket, and there is a problem that it is difficult to uniformly heat the foundry sand in the storage tank.

  Therefore, in the inventions of Patent Document 1 and Patent Document 2, gas is ejected from a nozzle hole disposed in the lower part of the storage tank, and the foundry sand in the storage tank is suspended or stirred by the gas thus ejected. The casting sand is heated by By heating the foundry sand while floating or stirring in the storage tank in this way, the foundry sand is heated while flowing in the storage tank so that the foundry sand in the storage tank is heated uniformly. It is what.

Japanese Patent Laid-Open No. 06-142837 (FIG. 2) JP 2001-321886 A (FIGS. 1 and 2)

  However, just floating or stirring the foundry sand with the gas ejected from the lower nozzle hole of the storage tank as in the inventions of Patent Documents 1 and 2, the entire foundry sand in the storage tank is floated or stirred. It ’s difficult. Therefore, even in the inventions of Patent Documents 1 and 2, it was still difficult to uniformly heat the foundry sand in the storage tank.

  This invention is made in view of said point, and aims at providing the heating apparatus of foundry sand which can stir the whole foundry sand in a storage tank, and can heat foundry sand uniformly. To do.

  The casting sand heating device according to the present invention includes a storage tank 10 that stores the casting sand, a gas supply device 201 that supplies the heating gas into the storage tank 10 so as to blow the heating gas upward from the lower portion thereof, The upper and lower openings of the convection cylinder 202 are formed in a cylindrical shape that is open at the top and bottom, and are provided in the storage tank 10 at a position where heated gas is blown into the cylinder from the opening at the lower end. The casting sand in the convection cylinder 202 blown up by the heated gas blown into the convection cylinder 202 is formed as an overflow port 203 that is blown out to the outside of the convection cylinder 202 in the storage tank 10, and on the outside of the convection cylinder 202. A sand inflow hole 204 through which casting sand flows into the convection cylinder 202 is formed on a side surface of the convection cylinder 202.

  According to the present invention, the foundry sand supplied to the storage tank 10 flows into the convection cylinder 202 from the sand inflow hole 204, and the foundry sand that has flowed into the convection cylinder 202 is convected by the heated gas blown from the gas supply device 201. The foundry sand that has been blown upward in the cylinder 202 and overflowed to the outside of the convection cylinder 202 from the overflow port 203 at the upper end flows into the convection cylinder 202 through the sand inflow hole 204. Thus, the foundry sand in the storage tank 10 is convected between the inside and the outside of the convection cylinder 202, and the entire foundry sand in the storage tank 10 can be agitated by convection. While sand is convected, the foundry sand can be heated with heated air that convects the foundry sand, and the foundry sand can be heated uniformly.

  In the present invention, the sand discharge port 205 is formed at the lower end of the storage tank 10, and the heated gas supplied from the gas supply device 201 is blown into the storage tank 10 through the sand discharge port 205. The convection cylinder 202 is arranged such that the opening at the lower end faces the sand discharge port 205.

  According to the present invention, the heated gas for convection of the foundry sand and for heating the foundry sand is stored in the storage tank 10 through the sand discharge port 205 for discharging the foundry sand in the storage tank 10. It is blown in, and it becomes unnecessary to provide the storage tank 10 with a special opening for blowing the heated gas into the storage tank 10, and the storage tank 10 can be formed in a simple structure.

  The present invention also includes a filter body 206 disposed so as to close the lower end opening of the sand discharge port 205. The filter body 206 includes a plate body 207 and a filter net 208 that allows gas to pass but does not allow foundry sand to pass. The plate body 207 is provided with a sand passage hole 209 and a vent hole 210, and the filter net 208 is disposed at the vent hole 210 so as to avoid the sand passage hole 209. The sand passage hole 209 serves as a passage when the foundry sand in the storage tank 10 is discharged from the sand discharge port 205, and the vent hole 210 is provided with the heated gas supplied from the gas supply device 201 in the storage tank 10. It becomes a passage when being blown into.

  According to the present invention, the heated gas supplied from the gas supply device 201 is closed in a state where the sand discharge port 205 of the storage tank 10 is closed by the filter body 206 at a portion other than the sand passage hole 209 serving as a casting sand discharge passage. The vent hole 210, which can be blown into the storage tank 10 through the vent hole 210 of the filter body 206 and in which the filter net 208 that does not allow the foundry sand to pass through, can be formed with a large diameter, and has a large air volume. Thus, the heated gas can be blown into the storage tank 10, and even if a large amount of foundry sand is stored in the storage tank 10, the foundry sand can be convected without hindrance.

  The filter body 206 is formed by overlapping a plurality of plate bodies 207 and a filter net 208 sandwiched between the plate bodies 207, and the sand passage holes 209 and the vent holes 210 of each plate body 207 are stacked in the vertical direction. Are provided so as to be arranged at the same position.

  In this way, the filter net 208 is sandwiched between the plate bodies 207 so that the filter net 208 can be brought into close contact with the plate body 207 without the need to fix it. The filter net 208 can be easily detached from the plate body 207, and the filter net 208 can be easily replaced or cleaned.

  In addition, the present invention is characterized by including an opening / closing tool 211 that is disposed in the storage tank 10 so as to be movable up and down, and that opens and closes the upper end of the sand passage hole 209 of the filter body 206 by vertical movement.

  According to the present invention, casting sand can be discharged from the sand discharge port 205 of the storage tank 10 through the sand passage hole 209 of the filter body 206, but the sand passage hole 209 is closed by the opening / closing tool 211. Thus, the entire amount of foundry sand in the storage tank 10 can be uniformly heated without causing a part of the foundry sand to enter the sand passage hole 209 from the storage tank 10.

  The present invention also includes a gas introduction body 215 formed by disposing a sand passage cylinder 214 inside a gas passage cylinder 213 having a connection port 212 connected to the gas supply device 201, and the gas passage cylinder 213 and the sand passage The vent hole 210 of the filter body 206 is located on the upper surface of the gas passage chamber 216 formed between the cylinders 214, and the opening at the upper end of the sand passage cylinder 214 matches the opening at the lower end of the sand passage hole 209 of the filter body 206. As described above, the gas introduction body 215 is arranged below the filter body 206.

  The gas supply device 201 is connected to the filter body 206 through the gas introduction body 215, but if the vent hole 210 of the filter body 206 is located on the upper surface of the gas passage chamber 216 of the gas introduction body 215, heating is performed. Gas can be supplied from the gas passage chamber 216 to the vent hole 210 and supplied to the storage tank 10, and it is not necessary to accurately align the vent hole 210 and the gas passage chamber 216. Thus, even if the filter body 206 is provided with a plurality of ventilation holes 210, the filter body 206 and the gas introduction body 215 can be disposed without any trouble.

  In the present invention, the filter body 206 is sandwiched between the lower surface of the sand discharge port 205 of the storage tank 10 and the upper surface of the gas introduction body 215, and at least one of the storage tank 10 and the gas introduction body 215 is vertically It is characterized in that it is formed so as to be movable in the direction of approaching and separating.

  According to this invention, the filter body 206 can be taken out by separating the storage tank 10 and the gas introduction body 215, and the filter net 208 of the filter body 206 can be easily replaced or cleaned. .

  In the present invention, the storage tank 10 is provided with a sand detection sensor 217 for detecting the position of the upper surface of the foundry sand in the convection cylinder 202 at a position facing the sand inflow hole 204 on the side surface of the convection cylinder 202. It is a feature.

  According to the present invention, the amount of foundry sand stored in the storage tank 10 can be detected based on the height of the upper surface of the foundry sand in the convection cylinder 202 detected by the sand detection sensor 217. Accordingly, the amount of foundry sand in the storage tank 10 can be kept constant by supplying the foundry sand to the storage tank 10.

  Further, the present invention is characterized in that a shielding body 218 is provided in the storage tank 10 above the convection cylinder 202 and covers the overflow port 203 at the upper end of the convection cylinder 202 through a gap through which foundry sand passes. To do.

  According to the present invention, the shielding body 218 can prevent the foundry sand in the convection cylinder 202 blown up by the heated gas from being scattered outside the storage tank 10.

  Further, the present invention is characterized in that the shield 218 is formed as an inclined guide surface 218 whose lower surface is inclined downward from the central portion to the outer peripheral portion.

  According to the present invention, when the foundry sand in the convection cylinder 202 blown up by the heated gas hits the shield 218, the foundry sand is guided to flow outside the convection cylinder 202 due to the inclination of the inclined guide surface 218 on the lower surface thereof. Therefore, convection of foundry sand inside and outside the convection cylinder 202 is performed smoothly.

  Further, the present invention is characterized in that a heat exchanger 220 for passing the refrigerant through the sand passage cylinder 214 of the gas introduction body 215 is provided.

  Heat of the heated gas passing through the gas passage chamber 216 acts on the sand passage tube 214 located in the gas passage chamber 216 of the sand passage tube 214, but heat exchange is performed when the temperature of the sand passage tube 214 rises. This can be prevented by cooling by the vessel 220 and can prevent the foundry sand from adhering to the inner periphery of the sand passage cylinder 214.

  Further, the present invention is characterized in that the gas supply device 201 includes a dehumidifier 221 that dehumidifies air and a heating blower 222 that heats and sends the dehumidified air.

  According to the present invention, heated air dehumidified and dried as a heated gas can be supplied to the storage tank 10, and can be heated without moistening the foundry sand.

  According to the present invention, the foundry sand supplied to the storage tank 10 flows into the convection cylinder 202 from the sand inflow hole 204, and the foundry sand that has flowed into the convection cylinder 202 is convected by the heated gas blown from the gas supply device 201. Cast sand that is blown upward in the cylinder 202 and overflows from the overflow port 203 at the upper end to the outside of the convection cylinder 202, and flows out of the convection cylinder 202 into the convection cylinder 202 through the sand inflow hole 204. Thus, the foundry sand in the storage tank 10 is convected between the inside and the outside of the convection cylinder 202, and the entire foundry sand in the storage tank 10 can be stirred by convection. Therefore, the casting sand can be heated with the heated air that convects the casting sand while the casting sand is convected in this way, and the casting sand can be heated uniformly.

It is sectional drawing which shows an example of the heating apparatus of the foundry sand which concerns on this invention. The apparatus same as the above is shown, (a) is a front view and (b) is a bottom view. It is a side view of an apparatus same as the above. The convection pipe | tube of an apparatus same as the above is shown, (a) is front sectional drawing, (b) is a top view. The shielding body of an apparatus same as the above is shown, (a) is front sectional drawing, (b) is a top view, (c) is a bottom view. The gas introduction body of an apparatus same as the above is shown, (a) is front sectional drawing, (b) is a top view, (c) is a bottom view. It shows a plate body constituting the filter body of the apparatus of the above, (a) is a bottom view of the plate body, (b) is a sectional view, (c) is a bottom view of another plate body, (d) is It is sectional drawing. It shows a plate body constituting the filter body of the apparatus of the above, (a) is a bottom view of the plate body, (b) is a sectional view, (c) is a bottom view of another plate body, (d) is It is sectional drawing. The filter body of an apparatus same as the above is shown, (a) is an exploded sectional view, (b) is a sectional view, and (c) is a partially enlarged sectional view.

  Embodiments of the present invention will be described below.

  As shown in FIGS. 1 and 2, the storage tank 10 is formed in a hopper shape in which the upper surface is open and the lower part is smaller in inner diameter, and a cylindrical shape such as a cylinder is formed at the lower end of the storage tank 10. A formed sand discharge port 205 is provided protruding downward. A convection cylinder 202 and a shield 218 are attached in the storage tank 10.

  As shown in FIG. 4, the convection cylinder 202 is formed in a cylindrical shape such as a cylinder opening up and down, and the diameter of the convection cylinder 202 is substantially the same as the inner diameter of the sand discharge port 205 of the storage tank 10. It is formed to have dimensions. Further, the convection tube 202 is formed so that sand inflow holes 204 are opened inward and outward at a plurality of equally spaced locations (three locations in the illustrated embodiment). Each sand inflow hole 204 is formed in a slot shape that is long in the vertical direction from the lower end portion of the convection cylinder 202 to the upper end portion. A mounting piece 230 is fixed to the outer peripheral surface of the convection cylinder 202 so as to protrude outward at a position between the sand inflow holes 204.

  A receiving piece 231 is fixed to the inner periphery of the lower part of the storage tank 10 so as to protrude inward, and a screw rod 232 is erected on the upper surface of the receiving piece 231. The receiving piece 231 and the screw rod 232 are provided at a plurality of locations corresponding to the attachment piece 230 of the convection cylinder 202. Then, the convection cylinder 202 is disposed in the storage tank 10, and a through hole 233 formed in the attachment piece 230 of the convection cylinder 202 that opens vertically is inserted into the screw rod 232 from the upper end and screwed into the screw rod 232. By tightening the attachment piece 230 from above and below at 234, the convection tube 202 is attached in the storage tank 10 as shown in FIG. The convection tube 202 is attached at a position where the opening at the lower end of the convection tube 202 faces and matches the opening at the upper end of the sand discharge port 205, and the opening at the lower end of the convection tube 202 is close to the opening at the upper end of the sand discharge port 205. The mounting height is set as follows. Here, the mounting height of the convection tube 202 can be adjusted and changed by changing the screwing position of the nut 234 screwed to the screw rod 232 in the vertical direction and adjusting the tightening position of the mounting piece 230. .

  As shown in FIG. 5, the shield 218 is formed in a conical (conical frustum) umbrella shape, and a circular through hole 236 that opens up and down is provided at the center. Since the shield 218 is thus conical, the lower surface of the shield 218 is formed as an inclined guide surface 219 that slopes downward from the center to the outer periphery. Receiving bosses 237 protrude from the upper surface of the shield 218 at a plurality of locations, and screw holes 238 are recessed in the upper surface of the receiving boss 237. A cylindrical guide tube 239 is disposed below the shield 218, and the guide tube is formed by connecting pieces 240 provided radially between the outer peripheral surface of the guide tube 239 and the inner peripheral surface of the shield 218. 239 is supported by the shield 218. The guide cylinder 239 is located immediately below the through hole 236, and the inner diameter of the guide cylinder 239 is the same as or slightly larger than the inner diameter of the through hole 236.

  As shown in FIGS. 1 to 3, the shield 218 is disposed and attached in the storage tank 10 at a position directly above the convection cylinder 202. That is, the lower end of the hanging screw rod 241 is screwed into the screw hole 238 of each receiving boss 237 of the shield 218. A support base 242 is installed over the center of the opening at the upper end of the storage tank 10 as shown in FIG. 2, and the hanging screw rod 241 is passed through the support base 242 from the lower side to the screw rod 241. The hanging screw rod 241 is fixed to the support base 242 by screwing the nut 243. In this way, the shield 216 can be suspended and supported on the support base 242 by the hanging screw rod 241. The diameter of the shield 218 is formed to be larger than the diameter of the convection cylinder 202. By disposing the shield 218 directly above the convection cylinder 202 with a gap, as shown in FIG. The opening can be covered with the shield 218. By adjusting the vertical position where the nut 243 is screwed onto the screw rod 241, the mounting height of the shield 216 can be adjusted, and the distance of the gap between the shield 218 and the convection cylinder 202 is adjusted. Is something that can be done.

  A cylinder mount 244 is provided on the support base 242 as shown in FIGS. 2 and 3, and an opening / closing cylinder 245 formed of an air cylinder or the like is attached to the cylinder mount 244 in a downward-facing arrangement. An opening / closing tool 211 is attached to the rod 245 a of the opening / closing tool cylinder 245. The opening / closing tool 211 includes a connecting rod 246 and an opening / closing stopper 247 attached to the lower end of the connecting rod 246. 1, the connecting rod 246 is connected to the rod 255a of the opening / closing cylinder 255 via the rod fitting 248 so that the connecting rod 246 is disposed at the center of the convection cylinder 202 through the passage 236 of the shield 218 and the guide cylinder 239. The upper end of the rod 246 is attached and attached. An opening / closing stopper 247 at the lower end of the opening / closing tool 211 is arranged in the sand discharge port 205 of the storage tank 10. The opening / closing tool 211 can be moved up and down by operating the opening / closing cylinder 245 to project and immerse the rod 245a.

  A gas supply device 201 that supplies heated gas to the storage tank 10 is connected to the storage tank 10 via a gas introduction body 215. As shown in FIG. 6, the gas introduction body 215 includes a gas passage cylinder 213 formed in a cylindrical shape such as a cylindrical opening and a similar sand passage cylinder 214 having a smaller diameter than the gas passage cylinder 213. The gas passage cylinder 213 is formed concentrically and fixed on the lower plate 251 having a through hole 250 at the center by welding or the like, thereby closing the opening on the lower surface of the gas passage cylinder 213. In addition, the lower end of the sand passage cylinder 214 is inserted into the through hole 250 and fixed to the lower plate 251. An upper plate 252 having a size larger than that of the lower plate 251 is attached to the upper end of the gas passage tube 213 by welding or the like, and an opening window 253 that is slightly smaller than the inner diameter of the gas passage tube 213 is formed on the upper plate 252. It is. The upper surface of the gas passage cylinder 213 is opened by the opening window 253, and is surrounded by the inner periphery of the gas passage cylinder 213, the outer periphery of the sand passage cylinder 214, and the lower plate 251, and the upper surface is opened by the opening window 253. A gas passage chamber 216 is formed. The gas passage cylinder 213 is provided with a ventilation connection pipe 254 so as to protrude outward, and the gas passage chamber 216 communicates with the connection port 212 on the inner periphery of the gas connection pipe 254. A cylindrical socket 257 is further attached to the gas passage cylinder 213. A fitting recess 255 having a width wider than the diameter dimension of the gas passage cylinder 213 is formed on the upper surface of the upper plate 252 so as to extend from one side end of the upper plate 252 to the other side end. Further, a ring-shaped spacer 256 having the same thickness as that of the upper plate 252 in the fitting recess 255 is attached to the upper end of the sand passage cylinder 214, and the sand passage cylinder 214 is open in communication with the top and bottom.

  A heat exchanger 220 made of a spiral tube is attached to the outer periphery of the sand passage cylinder 214 so that the sand passage cylinder 214 can be cooled by passing a refrigerant such as water from the refrigerant pipe 260 to the heat exchanger 220. It is. The refrigerant pipe 260 is hermetically passed through the socket 257, introduced into the gas passage chamber 216, and connected to both ends of the heat exchanger 220.

  The gas introduction body 215 is attached to the support beam 37 as shown in FIGS. That is, the support plate 262 is fixed on the support beam 37, and the gas introduction body 215 is fixed on the support plate 262. As shown in FIG. 2A, a pair of push-up cylinders 263 is attached to the support beam 37 on the lower side of the support plate 262 in an upward posture. A branch bar 264 is attached to the rod 263a of the push-up cylinder 263, and push-up bars 265 are attached to both ends of the branch bar 264 so as to protrude upward. Each of the four push-up bars 265 has a base portion formed as a large diameter portion 265a and a tip portion formed as a small diameter portion 265b. The large diameter portion 265a is slidably passed through a sleeve 266 provided on the support plate 262, and is thin. The diameter portion 265b protrudes upward. Further, as shown in FIGS. 6 (b) and 6 (c), insertion holes 267 are formed at four positions on the end portion of the upper plate 252 of the gas introduction body 215, and the narrow diameter portion of the push-up bar 265 is formed. 265b is inserted through the insertion hole 267 so as to be slidable up and down.

  On the other hand, a flange 268 projecting outward is provided on the outer periphery of the lower end of the sand discharge port 205 of the storage tank 10, and the small diameter of the push-up bar 265 inserted through the insertion hole 267 of the upper plate 252 of the gas introduction body 215. This flange 268 is fixedly coupled to the upper end of the portion 265b. Accordingly, the storage tank 10 is disposed and attached above the support beam 37 while being supported by the four push-up bars 265. When the push-up cylinder 263 is actuated to cause the rod 263a to protrude and dip up and down, the four push-up rods 265 move up and down via the branch bar 264, and accordingly the storage tank 10 is moved up and down. The vertical movement of the storage tank 10 allows the lower end of the sand discharge port 205 of the storage tank 10 and the upper surface of the gas introduction body 215 to be moved closer to and away from each other.

  A filter body 206 is interposed between the lower end of the sand discharge port 205 of the storage tank 10 and the upper surface of the gas introduction body 215. The filter body 206 is formed by vertically stacking a plate body 207 and a filter net 208. In the embodiment shown in the figure, the four plate bodies 207 and the two filter nets 208 are overlapped to form the filter body 207. It is designed to form. That is, as the plate 207, four sheets shown in FIGS. 7A, 7B, 8A, and 8B are used, and one set of FIGS. 7A and 7B is used. 8A and 8B are used as a set.

  A plate body 207a shown in FIGS. 7 (a) and 7 (b) is provided with a circular recess 270 on the lower surface of a square plate, a fitting hole 271 in the center, and a large number of concentric circles surrounding the fitting holes 271 in a plurality of rows. The pores 210a are formed at the recesses 270. A plate 207b shown in FIGS. 7C and 7D is provided with a circular convex portion 270 on the upper surface of the square plate, a sand passage hole 209a in the center, and a large number of concentric circles surrounding the sand passage holes 209a. The vent hole 210b is provided at the location of the protrusion 271. The vent holes 210a of the plate body 207a and the vent holes 210b of the plate body 207b are formed to have the same size and the same arrangement, and the fitting ring 273 is formed on the upper surface surrounding the sand passage hole 209a of the plate body 207b. Is protruding.

  Further, the filter net 208 is formed of a wire net or the like that does not allow the particles of foundry sand to pass through. The filter net 208a sandwiched between the plates 207a and 207b is formed in a circular shape having an outer diameter that is substantially the same as the inner diameter of the recess 270, as shown in FIG. An opening 274 having an inner diameter substantially equal to the diameter is formed.

  9A, the filter net 208a is placed between the plates 207a and 207b by disposing the filter mesh 208a between the plates 207a and 207b and overlapping the plates 207a and 207b. Can do. Here, the diameter and depth dimension of the concave portion 270 of the plate body 207a are formed substantially equal to the diameter and height dimension of the convex portion 270 of the plate body 207b, and the plate body 207a and the plate body 207b are formed in the concave portion 270. The filter net 208a is tightly sandwiched between the concave portion 270 and the convex portion 272 so that the convex portion 272 is fitted into the convex portion 272. At this time, the fitting ring 273 of the plate body 207b is fitted into the inner periphery of the fitting hole 271 of the plate body 207a through the opening 274 of the filter net 208a, and the air holes 210a of the plate body 207a and the plate. The vent holes 210b of the body 207b are aligned vertically. As described above, the air holes 210a of the plate body 207a and the air holes 210b of the plate body 207b are vertically aligned and communicated with each other, but the air holes 210a and the air holes 210b are connected as shown in FIG. 9C. A filter net 208a is interposed.

  A plate body 207c shown in FIGS. 8 (a) and 8 (b) is formed by providing a fitting hole 275 at the center of a square plate and providing a plurality of vent holes 210c surrounding the fitting holes 275 in a plurality of rows concentrically. . A plate 207d shown in FIGS. 8C and 8D is formed by providing a sand passage hole 209b at the center of the square plate and providing a plurality of vent holes 210d concentrically surrounding the sand passage hole 209b in a plurality of rows. is there. The vent hole 210c of the plate body 207c and the vent hole 210d of the plate body 207d are formed to have the same size and the same arrangement, and the fitting ring 276 is formed on the upper surface surrounding the sand passage hole 209b of the plate body 207d. Is protruding. Further, an opening 277 having an inner diameter substantially equal to the outer diameter of the fitting ring 276 is formed in the filter net 208b sandwiched between the plates 207c and 207d.

  Then, as shown in FIG. 9A, the filter net 208b is disposed between the plates 207c and 207d, and the plate 207c and 207d are overlapped, whereby the filter net 208b can be sandwiched between the plates 207c and 207d. . At this time, the fitting ring 276 of the plate body 207d is fitted into the inner periphery of the fitting hole 275 of the plate body 207c through the opening 277 of the filter net 208b. Each vent hole 210d of the body 207d is configured to match up and down. As described above, the air holes 210c of the plate body 207c and the air holes 210d of the plate body 207d are vertically aligned, but a filter is provided between the air holes 210c and the air holes 210d as shown in FIG. 9C. A network 208b is interposed.

  As described above, the filter mesh 208a is sandwiched between the plates 207a and 207b, the filter mesh 208b is sandwiched between the plates 207c and 207d, and the plates 207a and 207b are placed on the upper side and the plates 207c and 207d are placed on the plates 207c and 207d. The filter body 206 can be assembled by arranging it on the lower side and stacking up and down as shown in FIG. In this filter body 206, sand passage holes 209a and 209b provided at the centers of the plate bodies 207a and 207c are in close contact with each other and communicated vertically, and vent holes 210a to 210d provided in the plate bodies 207a to 207d are filter nets. They are in close contact with each other via 208a and 208b and communicate with each other. The plate bodies 207a and 207b and the plate bodies 207c and 207d may be detachably connected with metal fittings or the like so as not to be separated.

  As shown in FIGS. 1 to 3, the filter body 206 formed as described above is used by being disposed between the lower end of the sand discharge port 205 of the storage tank 10 and the upper end of the gas introduction body 215. Is. That is, when the push-up cylinder 263 is operated as described above and the rod 263a is lowered so as to be immersed in the push-up cylinder 263, the four push-up rods 265 move downward through the branch bar 264 and the storage tank 10 The filter body 206 can be sandwiched and attached between the sand discharge port 205 and the gas introduction body 215 of the storage tank 10. Here, the filter body 206 is attached in a state in which the lower end is fitted and positioned in the fitting recess 255 of the upper plate 251 of the gas introduction body 215.

  When the filter body 206 is attached between the sand discharge port 205 of the storage tank 10 and the gas introduction body 215 in this way, the opening at the lower end of the sand discharge port 205 of the storage tank 10 is the filter body 206 as shown in FIG. The opening window 253 on the upper surface of the gas passage chamber 216 of the gas introduction body 215 is closed on the lower surface of the filter body 206. The upper end opening of the sand passage cylinder 214 at the center of the gas introducing body 215 is in close contact with the lower end opening of the filter body 206 via the spacer 256.

  The numerous vent holes 201 of the filter body 206 are all located in the opening at the lower end of the sand discharge port 205 of the storage tank 10, and the upper opening of the numerous vent holes 201 is the opening at the lower end of the sand discharge port 205. It is arranged uniformly inside. In addition, the numerous vent holes 201 of the filter body 206 are all located within the opening on the upper surface of the gas passage chamber 216 of the gas introduction body 215, and the lower openings of the numerous vent holes 201 are formed on the upper surface of the gas passage chamber 216. It is arranged uniformly in the opening.

  In addition, a sand discharge cylinder 281 is connected to the lower end of the sand passage cylinder 214 of the gas introduction body 215. The sand discharge cylinder 281 is formed of an upper cylinder 281a, an intermediate cylinder 281b, and a lower cylinder 281c. As shown in FIG. 2, the intermediate cylinder 281b and the lower cylinder 281c are attached to the support beam 37 in a state where they are connected vertically. In addition, the lower cylinder 281 c protrudes below the support beam 37. The upper cylinder 281a has an upper end connected and fixed to the lower end of the sand passage cylinder 214, and the lower part of the upper cylinder 281a is inserted into the middle cylinder 281b. A discharge port 282 as shown in FIG. 2B is formed on the lower end surface of the sand discharge tube 281, and this discharge port 282 is opened and closed by a sand shutter 283.

  As shown in FIG. 2B, the sand shutter 283 is provided with a shutter hole 283 a and is disposed in contact with the lower surface of the discharge port 282 of the sand discharge tube 281. The sand shutter 283 is fixed to the tip of the cylinder rod 284 a of the shutter opening / closing cylinder 284, and the shutter opening / closing cylinder 284 is attached to the support beam 37. The sand shutter 283 is moved back and forth by a shutter opening / closing cylinder 284. When the sand shutter 283 is advanced and the shutter hole 283a of the sand shutter 283 matches the discharge port 282, the discharge port 282 is opened. In this state, the discharge port 282 can be closed with the sand shutter 283 by moving the sand shutter 283 backward with the shutter opening / closing cylinder 284. In the normal state, the discharge port 282 is closed by the sand shutter 283.

  A gas supply device 201 is connected to the connection port 212 of the gas introduction body 215 so that the heated gas is supplied from the gas supply device 201 to the gas passage chamber 216 of the gas introduction body 215. The heating gas is generally air, but any gas such as nitrogen gas can be used. In the embodiment of FIG. 2 (a), a dehumidifier is incorporated, a dehumidifier 221 that dehumidifies by sucking air in the atmosphere, a heating device such as a heater, and a blower device such as a fan are incorporated, and the dehumidifier 221 is incorporated. The gas supply device 201 is formed by the heating blower 222 that heats and sends out the dehumidified air flowing in from the air. It is desirable that the dehumidifier 221 has a dehumidifying ability capable of removing about 99.9% of moisture, and by using such dehumidified gas as the heated gas, the heated gas is stored as described later. It is possible to prevent the stored foundry sand from being moistened when supplied into the tank 10. In particular, when the foundry sand is a binder-coated sand, it is possible to prevent moisture from acting on the binder. The gas heating temperature by the heating blower 222 is not particularly limited, but when the foundry sand is a binder-coated sand, it is necessary to set it lower than the temperature at which the binder does not harden.

  The storage tank 10 stores foundry sand used for mold production. As casting sand, fireproof aggregate itself such as dredged sand, mountain sand, alumina sand, olivine sand, chromite sand, zircon sand, mullite sand, artificial sand, etc. can be used, but the mold is manufactured by the shell mold method. In the case of the storage tank 10 attached to the apparatus, as the foundry sand to be stored, the refractory aggregate is coated with a solid binder by mixing the refractory aggregate with a binder. Binder coated sand is used. As the binder, it is common to use thermosetting resins such as phenol resins and furan resins. In addition to thermosetting resins, sugars, water-soluble inorganic compounds, water-soluble thermoplastic resins, etc. It can also be used.

  When heating the foundry sand stored in the storage tank 10, first, the gas supply device 201 is operated to supply the heated gas by blowing it into the gas passage chamber 216 of the gas introduction body 215 from the connection port 212. The heated gas flowing into the gas passage chamber 216 passes through the vent holes 210 of the filter body 206 from the opening window 253 on the upper surface, and is blown into the storage tank 10 through the sand discharge port 205 at the lower end.

  At this time, the opening / closing tool 211 is pushed down by the action of lowering the rod 245a of the opening / closing cylinder 245, and the opening at the upper end of the sand passage hole 209 of the filter body 206 is closed by the opening / closing stopper 247 at the lower end. Yes. Further, the vent hole 210 of the filter body 206 is closed by a filter net 208 sandwiched between the plate bodies 207 as shown in FIG. 9C. Therefore, the foundry sand in the storage tank 10 does not flow out through the vent hole 210 of the filter body 206, and the heated gas passes through the filter net 208 and is therefore blown into the storage tank 10 through the vent hole 210. .

  Thus, when heated gas is blown upward into the storage tank 10 from the sand discharge port 205 at the lower end, the foundry sand in the storage tank 10 is blown upward by this heated gas. And since the opening part of the lower end of the convection cylinder 202 is facing immediately above the opening part of the upper end of the sand discharge port 205, the heated gas will be blown upward into the convection cylinder 202, and the convection cylinder The foundry sand in 202 is blown up with heated gas. The foundry sand blown up in the convection cylinder 202 is overflowed and blown out to the outside of the convection cylinder 202 as indicated by a chain line arrow in FIG. Further, the foundry sand that overflows the upper end of the convection cylinder 202 and exits to the outside of the convection cylinder 202 in this manner flows into the convection cylinder 202 through the sand inflow hole 204 as indicated by a chain line arrow in FIG.

  In this way, by blowing up the foundry sand in the convection cylinder 202 with heated gas, the foundry sand overflows from the overflow port 203 at the upper end to the outside of the convection cylinder 202, and the foundry sand that has come out of the convection cylinder 202 is sand. It returns to the inside of the convection cylinder 202 from the inflow hole 204, and the foundry sand in the storage tank 10 can be convected between the inside and the outside of the convection cylinder 202. Accordingly, the foundry sand can be convected with heated gas in the storage tank 10 and heated while greatly stirring, and the foundry sand in the storage tank 10 can be heated uniformly. In addition, by adjusting the mounting height of the convection cylinder 202 along the screw rod 232 and forming a gap between the lower end of the convection cylinder 202 and the upper end of the sand discharge port 205, the convection cylinder 202 can be also removed from this gap. The outer foundry sand can flow into the convection cylinder 202, but if this gap is too large, the casting sand blown up by the heated gas may flow backward from the convection cylinder 202 to the outside. Absent.

  Here, when the foundry sand in the convection cylinder 202 is blown up with the heated gas, if the foundry sand is blown up vigorously, it may be scattered to the outside of the storage tank 10. In particular, small sand particles and binders peeled from the binder-coated sand are easily blown away. For this reason, a shield 218 is disposed above the overflow port 203 at the upper end of the convection cylinder 202 so that such scattering of foundry sand is blocked by the shield 218 and prevented. At this time, since the lower surface of the shield 218 is formed as an inclined guide surface 218 that inclines downward from the central portion to the outer peripheral portion, when the blown casting sand hits the shield 218, the lower surface of the inclined guide surface 218 of the lower surface is formed. By the inclination, the foundry sand is guided to flow outside the convection cylinder 202. Therefore, the convection of the foundry sand inside and outside the convection cylinder 202 can be smoothly performed by the shield 218.

  The foundry sand preheated while stirring with a heated gas as described above is discharged from the storage tank 10 in order to produce a mold by a shell mold method or the like. When discharging the foundry sand from the storage tank 10, first, the supply of the heated gas from the gas supply device 201 to the storage tank 10 is stopped, and the opening / closing cylinder 245 is operated to move the rod 245 a upward, thereby opening and closing the tool 211. Is pulled up and the opening / closing plug 247 is separated from the sand passage hole 209 of the filter body 206, thereby opening the upper end of the sand passage hole 209. When the opening at the upper end of the sand passage hole 209 is thus opened, the foundry sand in the storage tank 10 goes out from the sand passage hole 209 to the sand discharge cylinder 281 through the sand passage cylinder 214 of the gas introduction body 215.

  As described above, the casting sand is temporarily retained in the sand passage hole 209, the sand passage cylinder 214, and the sand discharge cylinder 281. However, the sand passage cylinder 214 of the gas introduction body 215 is surrounded by the gas passage chamber 216. Therefore, the heat of the heated gas is acting, and the sand passage cylinder 214 may become high temperature. When the foundry sand is a binder-coated sand, if the sand passage cylinder 214 is at a high temperature, the binder of the binder-coated sand may adhere to the inner periphery of the sand passage cylinder 214 or the like. . For this reason, the sand passage cylinder 214 is provided with a heat exchanger 220 through which the refrigerant passes, and the sand passage cylinder 214 is cooled by the heat exchanger 220 to suppress the temperature rise.

  After opening the opening / closing plug 247 of the opening / closing tool 211 to open the sand passage hole 209 of the filter body 206 as described above, the shutter opening / closing cylinder 284 is operated, the sand shutter 283 is advanced, and the shutter hole 283a is moved to the sand discharge cylinder 281. The outlet 282 is opened by matching with the outlet 282. By opening the discharge port 282 in this manner, the foundry sand in the storage tank 10 is discharged from the sand discharge port 205 through the sand passage hole 209, the sand passage tube 214, and the sand discharge tube 281. When the foundry sand in the storage tank 10 is discharged, the opening / closing cylinder 245 is operated to close the upper end opening of the sand passage hole 209 of the filter body 206 with the opening / closing stopper 247 of the opening / closing tool 211, and further to the sand passage hole 209, sand. The shutter opening / closing cylinder 284 is operated at the timing when the casting sand in the passage cylinder 214 and the sand discharge cylinder 281 is discharged, and the sand shutter 283 closes the discharge port 282 of the sand discharge cylinder 281.

  Here, as shown in FIG. 1, a sand detection sensor 217 formed by a level sensor or the like is detachably provided on the side wall of the storage tank 10. The sand detection sensor 217 is provided at a position facing one sand inflow hole 204 provided in the convection cylinder 202, and detects the height of the upper surface of the foundry sand stored in the convection cylinder 202 through the sand inflow hole 204. It is what you do. In the embodiment shown in FIGS. 1 and 3, the sand detection sensors 217 are provided at the upper part and the lower part, and the sand detection sensors 217a and 217b can be attached to the upper part and the lower part at one part, and the lower part is provided at one place. The sand detection sensor 217c can be attached to the head. In addition, the detection of the height of the upper surface of the foundry sand by the sand detection sensor 217 is performed in a state where the blowing of the heated gas from the gas supply device 201 into the storage tank 10 is stopped.

  For example, the following control can be performed using the sand detection sensor 217. After the casting sand in the storage tank 10 is discharged as described above, the opening / closing cylinder 245 is operated and the upper end opening of the sand passage hole 209 of the filter body 206 is closed by the opening / closing plug 247 of the opening / closing tool 211. Thereafter, new foundry sand is supplied into the storage tank 10 from the opening on the upper surface. When the foundry sand is supplied into the storage tank 10, the height of the upper surface of the foundry sand in the storage tank 10 gradually increases. Therefore, when the sand detection sensor 217 detects that the upper surface of the foundry sand has reached the height of any one of the sand detection sensors 217 selected from the plurality of sand detection sensors 217a, 217b, and 217c, it is stored. Supply of foundry sand to the tank 10 is stopped. Therefore, a predetermined amount of foundry sand can be supplied into the storage tank 10 by controlling the amount of foundry sand supplied to the storage tank 10 by its height. The amount of foundry sand supplied into the storage tank 10 can be changed depending on which height of the plurality of sand detection sensors 217a, 217b, and 217c is selected. Thereafter, the supply of the heated gas from the gas supply device 201 to the storage tank 10 is restarted, and the foundry sand newly supplied into the storage tank 10 is heated.

  As described above, the sand detection sensor 217 detects the height of the upper surface of the foundry sand in the storage tank 10 and can control the amount of the foundry sand supplied to the storage tank 10 to a certain amount. A certain amount of foundry sand can be discharged from the storage tank 10 after heating. Here, in the embodiment of FIGS. 1 and 3, a plurality of upper and lower sand detection sensors 217 are attached to the storage tank 10, and one of the plurality of sand detection sensors 217 is selectively used to store the sand. Although the height of the upper surface of the foundry sand in the tank 10 is detected, only the sand detection sensor 217 at a height according to the amount of foundry sand supplied into the storage tank 10 is attached to the storage tank 10. It may be.

  As described above, when the heated gas is blown from the gas supply device 201 into the storage tank 10 through the vent holes 210 of the filter body 206 to heat the foundry sand, the vent holes 210 of the filter body 206 are blocked by the filter net 208. Therefore, the foundry sand in the storage tank 10 does not pass through the vent hole 210 of the filter body 206. However, the mesh of the filter net 208 is gradually clogged with fine powder of foundry sand, fine powder of binder of binder-coated sand, and the like, and the efficiency of passing the heated gas through the vent hole 210 is deteriorated. For this reason, it is necessary to clean or replace the filter network 208 regularly or irregularly. In order to clean and replace the filter net 208 as described above, the push-up cylinder 263 is operated to move the rod 263a upward, and the storage tank 10 is pushed up. When the storage tank 10 is pushed up in this way, the lower end of the sand discharge port 205 of the storage tank 10 is separated from the upper surface of the filter body 206, so that the filter body 206 can be taken out between the storage tank 10 and the gas introduction body 215. In this way, the filter net 208 can be removed from between the plate bodies 207 with the filter body 206 removed, and the filter net 208 can be easily cleaned or replaced. In addition, as shown in FIG. 9, the vent hole 210a of the plate body 207a at the upper end of the filter body 206 is opened so as to expand upward. By forming the opening of the vent hole 210 at the upper end of the filter body 206 in this way, fine powder of foundry sand or fine powder of binder is adhered between the inner periphery of the vent hole 210 and the upper surface of the filter net 208. It becomes difficult to do.

DESCRIPTION OF SYMBOLS 10 Reservoir 201 Gas supply device 202 Convection cylinder 203 Overflow port 204 Sand inflow hole 205 Sand discharge port 206 Filter body 207 Plate body 208 Filter net 209 Sand passage hole 201 Vent hole 211 Opening and closing tool 212 Connection port 213 Gas passage cylinder 214 Sand passage Tube 215 Gas introduction body 216 Gas passage chamber 217 Sand detection sensor 218 Shield body 219 Inclined guide surface 220 Heat exchanger 221 Dehumidifier 222 Heating blower

Claims (12)

  A storage tank for storing the foundry sand, a gas supply device for supplying the heating gas into the storage tank so as to blow the heating gas upward from the lower part thereof, and a cylindrical shape whose upper and lower sides are open. A convection cylinder disposed in the storage tank at a position blown into the cylinder from the opening of the convection cylinder, and the opening at the upper end of the convection cylinder is foundry sand in the convection cylinder blown up by the heated gas blown into the convection cylinder Is formed as an overflow port overflowing to the outside of the convection cylinder in the storage tank, and a sand inflow hole through which the casting sand outside the convection cylinder flows into the convection cylinder is formed on the side surface of the convection cylinder. A casting sand heating device.   A sand discharge port is formed at the lower end of the storage tank, and the heated gas supplied from the gas supply device is blown into the storage tank through the sand discharge port. 2. The foundry sand heating apparatus according to claim 1, wherein the sand sand heating apparatus is disposed so as to face the sand discharge port.   The filter body is arranged so as to close the opening at the lower end of the sand discharge port. The filter body is formed by vertically stacking a plate body and a filter net that allows gas to pass but does not allow foundry sand to pass through. Is provided with a sand passage hole and a vent hole, and the filter net is arranged at the vent hole area, avoiding the sand passage hole area. 3. The air passage according to claim 1, wherein the air hole serves as a passage when the heated gas supplied from the gas supply device is blown into the storage tank. The casting sand heating apparatus as described.   The filter body is formed by overlapping a plurality of plate bodies and a filter net sandwiched between the plate bodies, and the sand passage holes and vent holes of each plate body are arranged at the same position in a state where they are stacked one above the other. 4. The foundry sand heating device according to claim 3, wherein the foundry sand heating device is provided.   5. The foundry sand heating device according to claim 3, further comprising an opening / closing tool disposed in the storage tank so as to be movable up and down and opening and closing an upper end of the sand passage hole of the filter body by moving up and down. .   A gas introducing chamber formed by disposing a sand passage cylinder inside a gas passage cylinder having a connection port connected to the gas supply device, and formed between the gas passage cylinder and the sand passage cylinder. The gas introduction body is arranged below the filter body so that the vent hole of the filter body is located on the upper surface and the opening of the upper end of the sand passage cylinder matches the opening of the lower end of the sand passage hole of the filter body. The foundry sand heating apparatus according to any one of claims 3 to 5.   The filter body is sandwiched between the lower surface of the sand discharge port of the storage tank and the upper surface of the gas introduction body, and at least one of the storage tank and the gas introduction body is formed so as to be freely movable in the vertical direction. The foundry sand heating apparatus according to claim 6, wherein the foundry sand heating apparatus is provided.   8. A sand detection sensor for detecting the position of the upper surface of the foundry sand in the convection cylinder at a position facing the sand inflow hole on the side surface of the convection cylinder in the storage tank. A casting sand heating apparatus according to claim 1.   9. The shield according to claim 1, further comprising: a shielding member disposed at a position above the convection cylinder in the storage tank and covering an overflow port at an upper end of the convection cylinder through a gap through which the foundry sand passes. The casting sand heating apparatus as described.   10. The foundry sand heating apparatus according to claim 9, wherein the shield is formed as an inclined guide surface whose lower surface is inclined downward from the central portion to the outer peripheral portion.   11. The foundry sand heating apparatus according to claim 6, further comprising a heat exchanger for passing the refrigerant through the sand passage cylinder of the gas introduction body.   The casting according to any one of claims 1 to 11, wherein the gas supply device includes a dehumidifier that dehumidifies air and a heating blower that heats and sends the dehumidified air. Sand heating device.

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