JP2009279647A - Evaporative pattern casting apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an evaporative pattern casting apparatus which achieves the compaction strengthening of cast sand over the whole region of the upper and lower parts upon pouring, and yet can suck and remove generated gas and efficiently fluidizes whole cast sand vertically upon releasing a flask. <P>SOLUTION: The evaporative pattern casting apparatus is constituted in such a way that the lower part of the flask is provided with a flow passage part to form an air passage, the air flow passage is provided with a pressure reduction means and an air feed means successively, and cast sand in the flask is compaction-strengthened, stirred and fluidized. At least one suction pipe is connected from the flow passage part toward above, and also, a check valve allowing the suction and exhaust of gas from and to the suction pipe is provided. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vanishing model casting apparatus.

Conventionally, in the vanishing model casting method using the vanishing model, the operation is generally performed in the following steps.
First, the disappearance model corresponding to the casting product is one that is molded with polystyrene foam, this is foamed raw material beads using a preliminary foaming machine, molded using a molding machine, and then applied, Completed by drying.
This vanishing model is installed in a state where floor sand is put in a casting frame, and the casting sand is thrown in and the casting sand is hardened by a vibration table. Various types of apparatuses are widely used as the vibration table.

FIG. 7 is a vertical side view of the completed casting frame.
1 is a casting frame (flask), 2 is a casting sand of no binder, 3 is a disappearance model, and 4 is a mortar. Reference numeral 5 denotes a vinyl sheet placed on the casting sand 2 for exhibiting a decompression effect. Reference numeral 6 denotes a duct-like (rectangular cross-section) flow path provided at the bottom of the casting frame 1 for decompression. Reference numeral 7 denotes an expander for protecting the flow path 6. The flow path section 6 forms an air flow path 13, which is connected to a decompression means 9 outside the casting frame 1, that is, a vacuum pump, for example, via a vacuum hose 8.

  Thus, in the disappearance model casting method, the casting frame 1 is decompressed using the decompression means 9 at the time of pouring, because the foamed model burns with the pouring and generates a large amount of gas. In order to prevent this from happening, it is possible to suck and exhaust this, and to maintain the state in which the non-binder casting sand 2 is compactly filled with the vibration table during pouring.

As such a disappearance model casting method, various proposals have been made for a long time, and examples thereof include the following techniques.
JP-A-6-114496. JP-A-8-1685.

In the disappearance model casting method described above, when the molten metal is poured while decompressing the casting frame 1, the hot water enters while burning the disappearance model 3, and the generated gas is sucked by the decompression means 9.
By doing in this way, pouring can be performed well, but unraveling is performed using a troublesome method of reversing the casting frame 1 using a crane (or automatic reversing machine) when the hot water solidifies. I had to.
According to such a method, a large amount of dust and hot air is generated, and the casting sand in contact with the casting product is discharged at a high temperature of 400 ° C. to 500 ° C. Must be mixed with cold sand and cooled. Moreover, in order to cope with dust generation, there was a problem that a large hood and a dust collector had to be laid.

  Therefore, in view of the present situation, the present inventor can easily remove the cast product without laying a large dust removing device and inverting the cast frame in the dismantling work in the disappearance model casting. At the same time, it was proposed and considered to be able to cool the entire casting sand quickly.

  That is, as shown in FIG. 9 to FIG. 11, the vanishing model 3 is installed in the casting frame 1, and the air flow path 13 is formed by providing the flow path portion 6 having the flow path function at the lower portion of the casting frame 1. A vanishing model casting apparatus in which a decompression means 10 is connected to the air flow path 13 and the casting frame 1 is decompressed during pouring to suck the generated gas and strengthen the consolidation of the casting sand in the casting frame 1. The air supply means 14 for injecting compressed air into the flow path portion 6 below the casting frame 1 is provided so that the casting sand 2 of the casting frame 1 is stirred and fluidized.

  As a result, it is possible to easily perform the unpacking work in the disappearance model casting without laying a large dust removing device and without inverting the casting frame 1 while simultaneously injecting the entire casting sand by injecting compressed air. Remarkably, the casting sand 2 can be liquefied, the pressure is released, the casting product can be easily taken out (using a crane), and the casting sand 2 can be quickly cooled and post-treated at the same time. This has led to a great effect.

  However, although the above-mentioned countermeasures have achieved a certain purpose, in order to maintain the suction of the gas generated during pouring and the strengthening of the compaction of the casting sand 2, the above-described casting frame 1 is simply placed at the lower part. In the structure in which suction is performed by providing the flow path section 6, the casting frame 1 has a depth (there are various sizes), and there is a disappeared model (a poured casting instead of this) at the center position. From this, it was found that the distance is too long and insufficient to suck the gas from the upper position and strengthen the consolidation of the casting sand 2 at the upper position.

Then, this inventor considered connecting the suction pipe extended upwards from the flow path part 6 of the lower part. Of course, in consideration of the fact that the pipe does not get in the way of the disappearance model at the center (the cast casting that replaces this) and that the four corners of the casting frame are difficult to suck, for example, It was considered to arrange them at four corners (appropriate number and position were implemented).
As a result, the suction action is exerted from the perforation of the pipe extending upward, and the gas suction to the upper position of the casting frame 1 and the consolidation strengthening of the casting sand can be improved, but a new problem occurs. did.

  That is, while the performance during pouring has been improved, the pipe having the above-mentioned perforations is used when the entire casting sand is mixed and agitated by injecting compressed air at the time of releasing the frame to liquefy the casting sand 2. 1 near the top surface of the casting sand 2, the compressed air will immediately escape to the top surface of the casting sand from the perforation at the top of the pipe with low resistance. This is where the casting sand 2 is desired to be stirred and fluidized from the bottom (the resistance is large at the bottom), and this does not function properly.

  In view of such problems, the present invention is capable of sucking and removing the generated gas while having a simple structure and capable of strengthening the consolidation of the casting sand over the entire upper and lower sides during pouring, and at the time of releasing the frame. An object of the present invention is to provide a vanishing model casting apparatus capable of efficiently fluidizing the whole over the upper and lower sides.

In order to solve the above-described problem, the vanishing model casting apparatus according to the present invention is configured such that the vanishing model is installed in a casting frame, and a flow channel unit having a channel function is provided at a lower portion of the casting frame, so that an air channel is provided. A pressure reducing means is connected to the air flow path, and the casting frame is decompressed during pouring so as to suck the generated gas and strengthen the consolidation of the casting sand in the casting frame; The vanishing model casting apparatus is provided with an air supply means for injecting compressed air into the casting frame and configured to stir and flow the casting sand of the casting frame,
At least one suction pipe is connected upward from the flow path portion, and a plurality of suction holes are perforated at predetermined positions in the axial direction of the suction pipe, and
A check valve that prevents the compressed air from being pressed into the suction pipe from the flow path portion by the air supply means, and allows the gas to be sucked and discharged from the suction pipe through the flow path portion by the decompression means; Provided,
It is characterized by

As the disappearance model used in the present invention, styrene foam is mainly used, but in addition, it may be a disappearance model made of a photo-curing resin, and other existing disappearance models can be applied.
In addition, the compressed air to be injected may be mixed or replaced with an inert gas such as nitrogen in addition to the normal atmosphere.

  The check valve may be provided at any position as long as the purpose can be achieved. For example, a position near the lower end of the suction pipe, i.e., the vicinity of the root portion with respect to the flow path portion. Although it may be mentioned, it may be slightly above, and may be arranged above the position where the suction holes below the plurality of suction holes are perforated. That is, the flow of the molding sand is inhibited by the escape of the compressed air directly from the upper suction hole at the position where the discharge resistance is small to the upper surface of the casting sand, so if the suction hole is located at a relatively deep position Even if the compressed air is discharged from here, it can sufficiently contribute to the flow of the casting sand. Therefore, in some cases, even if a check valve is provided near the intermediate position in the vertical direction of the suction pipe, the object of the present invention ( The fluidization of the cast sand is achieved and may be anywhere as long as it exhibits the functions described above.

According to the apparatus of the present invention, the unpacking work in the disappearance model casting can be easily performed without laying a large dust removing device and without inverting the casting frame, while simultaneously injecting compressed air. The entire casting sand can be mixed and agitated, the casting sand can be liquefied, the pressure applied to the casting product can be released, and the casting product can be taken out easily. While the consolidation of casting sand and gas suction can be performed over substantially the entire area, a remarkable effect is achieved in that the stirring and mixing of the casting sand can be efficiently performed over the entire area of the casting frame during the unraveling.
Other specific effects of the present invention will be apparent from the following description.

In carrying out the present invention, it is preferable that the check valve is provided in the vicinity of the lower end portion of the suction pipe.
Thus, with a simple structure in which a check valve is simply provided in the vicinity of the lower end portion of the suction pipe, the air supply means prevents the compressed air from being pressed into the suction pipe from the flow path portion, and The function of allowing the gas to be sucked and discharged from the suction pipe through the flow path portion by the pressure reducing means can be exhibited, and the present invention can be implemented without performing any significant structural modification.
In addition, laying the check valve on the pipe in this way can be performed with a simple structural modification, leading to cost reduction.

Further, it is preferable that a plurality of the suction pipes are provided, these suction pipes are connected to the flow path portion via a collecting pipe, and one check valve is provided in the collecting pipe.
As described above, when a plurality of suction pipes are provided, a check valve may be provided for each suction pipe. However, by providing such a collecting pipe and providing one check valve therefor, a plurality of check pipes may be provided. The function of the check valve can be exhibited for all of the suction pipes, and as a result, the cost can be reduced.

Furthermore, it is preferable that the suction pipes are respectively arranged at positions near the four corners of the casting frame.
Thus, by arranging the suction pipes in the vicinity of the four corners of the casting frame, it is possible to expect a sufficient effect even at places where the four corners of the casting frame are inherently difficult to perform the suction, Consolidation strengthening and gas suction exclusion can be performed efficiently over the entire casting frame.

Moreover, it is preferable that at least the suction port of the suction pipe is covered with a mesh.
In this way, the suction port is covered with the mesh to prevent casting sand from entering the suction pipe from the suction port when casting sand is put into the casting frame and when consolidation of the casting sand is strengthened by vibration, etc. There is no possibility that the function of consolidation strengthening of casting sand during pouring and the function of negative pressure suction for exhausting gas will be impaired in advance.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a longitudinal side view of a casting frame in a vanishing model casting apparatus showing pressure reduction and FIG. 2 is pressure feeding. In the figure, 1 is a casting frame (flask), 2 is no binder casting sand, 3 is a disappearance model, and 4 is a boiled bowl. Reference numeral 5 denotes a vinyl sheet placed on the casting sand 2 for exhibiting a decompression effect. In addition, although the said 1 m square x 1 m high thing is used here, the thing of 2 m square x 2 m height or 0.5 m square x 0.5 m height is used suitably as the said casting frame 1 here. Used.

In the figure, reference numeral 20 denotes suction pipes arranged at the four corners of the casting frame 1, and suction ports 20 a are perforated at predetermined positions in the longitudinal direction, here four (or five), and the base ends thereof. The section is connected to the flow path section 6 described below. Here, the suction port 20a is a steel pipe having an outer diameter of 20 mm and a diameter of 10 mm. However, the suction port 20a may be an appropriate steel pipe having an outer diameter of about 30 mm and a suction port 20a having a diameter of about 30 mm.
A check valve 21 is installed inside the base end of the suction pipe 20 to allow suction from the suction port 20a to the flow path section 6, but is compressed from the flow path section 6. The inflow of air is configured to be blocked. As the check valve 21, a normal ready-made valve is used, and detailed description thereof is omitted here. The outside of the suction pipe 20 is covered with a mesh 22 (virtual line drawing) to prevent the sand clogging 2 from entering the suction port 20a and causing clogging.

  As shown in FIGS. 3 and 4, reference numeral 6 denotes a duct-shaped flow path portion (rectangular section, E-shaped in a plan view) provided at the bottom of the casting frame 1 for performing pressure reduction and pressure feeding. The band (mesh) 7 that protects the flow path section 6 is disposed immediately above the flow path section 6, but is not shown here (see FIGS. 1 and 2). Suction / exhaust ports 6a are formed at predetermined positions on the side wall of the flow path portion 6 (three for one row of E characters, three on each side of the central portion of the E character). However, it may be 4 places). And the discharge port 17 of the casting sand 2 is provided in the opposite side to the air supply port 18 to the said flow-path part 6 of the bottom part of the casting frame 1, and a plug (plug) is detachably fitted in there. Has been.

  The flow path portion 6 forms an air flow path 13, which is a decompression means 10 (also serving as an air supply means 14) outside the casting frame 1 via a vacuum hose 8, that is, here, a roots type blower. It is connected to the. In FIG. 2, reference numeral 11 denotes a crane hook for taking out the cast product 12 at the time of releasing the frame. The suction pressure of the decompression means 10 is about −50 KPa.

  The piping by the vacuum hose 8 is provided with three-way valves 14 and 15 as switching valves. When suction is performed during casting, the three-way valve 14 is opened to the atmosphere, and when sending compressed air, the three-way valve 15 is provided. It is configured to be released to the atmosphere.

In this embodiment, an 11 KW roots type blower is used. This Roots type blower is used to achieve the purpose of decompression of the casting frame and air injection (gas exhaust, casting sand flow and cooling) in light of the conditions of the disappearance model and the cast product.
This 11 KW Roots-type blower can send a sufficient air volume to generate the wind speed. That is, when the wind speed is 10 m and the casting frame is a square of 1 m, it is 10 cubic meters / minute. However, it can be implemented with a capacity of 5 to 20 m cubic meters / minute. The press-fitting pressure of the casting frame 1 to the casting sand 2 is 15 to 30 KPa (P = 15H, 1 m height is 15 KPa, and 2 m height is 30 KPa). What is used as the casting sand 2 that flows with such an air volume has an average particle size of about 500 μm, but has a relatively wide particle size distribution.

  The casting frame 1 is decompressed using the decompression means 10 at the time of pouring. The reason is that a large amount of gas is generated by burning the foamed model with pouring, so that it is exhausted. At this time, it is for maintaining the state in which the no-sand casting sand 2 is compactly filled with the vibration table so as not to lose its shape.

Then, the unpacking method of the present invention is carried out as follows.
First, the disappearance model 3 is installed in the casting frame 1 with the floor sand in the state. The cast frame 1 is provided with a flow path portion 6 and an extract band 7 for protecting the same at the bottom. The casting frame 1 is filled with casting sand 2 with a vibration table (not shown) or the like, and is brought into a compacted state around the vanishing model 3 (see FIG. 1). Thereafter, the vinyl sheet 5 is put on the upper surface of the casting frame 1.

  In this state, pouring is performed. At that time, the decompression means 10 of the roots type blower is operated, and the three-way valve 14 as the switching valve is opened to the atmosphere (the three-way valve 15 is closed). The gas generated by evacuating the inside of the casting frame 1 through the air (the vinyl sheet 5 blocks outside air suction), compacting the cast sand so that it does not lose its shape during pouring and burning the disappearing model Is sucked and exhausted to the outside.

  After about 5 minutes, when the hot water solidifies, the three-way valve 14 is closed, the three-way valve 14 is closed, the three-way valve 15 is opened to the atmosphere, and the pressure reducing means 10 is driven to exert a blowing function. This is operated as the air supply means 14. Then, compressed air is supplied to the inside of the cast frame 1 from the flow path portion 6 below the cast frame 1 through the flow path portion 6. At this time, the suction pipe 20 prevents passage of compressed air by a check valve 21 provided at a lower end portion thereof.

  At this time, the vinyl sheet 5 is removed in advance. At this time, the flow velocity of air passing through the casting sand 2 is set to about 10 m / min. As a result, the non-binder casting sand 2 flows and is stirred, and the casting is mixed with the thick casting sand 2 in the vicinity of the product and the relatively cold casting sand 2 at a distant position to cause heat exchange to cool the whole. The temperature drops to about 100 ° C. Although this temperature depends on the air volume and the blowing time, it is sufficient that the temperature is 70 ° C. to 130 ° C. Of course, the object of the present invention can be achieved even in the vicinity of this temperature.

The graph of FIG.6 and FIG.7 shows the result of having experimented about making the sand 2 flow by blowing this compressed air into the sand 2 and aiming at temperature fall rapidly.
FIG. 6 shows an experiment in which this method was performed. The intermediate part of the casting sand placed in a predetermined cylindrical container was heated to a higher temperature (180 ° C.) than the casting sand at the upper and lower positions, and then compressed. It is understood that air is sent from below at 10 m / min, and cooling is quick due to the flow and stirring of the casting sand.
FIG. 7 shows the temperature drop when the casting sand is heated under similar conditions, but is naturally cooled.
From the comparison between the two, it can be seen that the flow of casting sand due to injection of compressed air and the temperature drop due to mixing are remarkable.

Thereafter, in a state where the casting sand 2 is fluidized and stirred by the compressed air, the cast product 12 is suspended by the crane using the hook 11 and is taken out from the casting frame 1.
Thus, the state in which the casting sand 2 is flowed by the compressed air is a liquefied state, which is equivalent to the absence of accumulated sand pressure, and can be easily pulled out. There is no need to invert the frame 1 and therefore less dust is generated.
Moreover, the cooled casting sand 2 is discharged | emitted outside from the discharge port 17 of the lower part of the casting frame 1 from which the plug 18 was extracted in the state in which compressed air is supplied.

As described above, when air is injected, the flow path used for pressure reduction during pouring is used as it is, and air is press-fitted through this to prepare and create a flow path for air pressure feeding. There is no need and work is easy.
In the embodiment of the present invention, the vacuum pump as the decompression means and the blower as the air supply means are used together, but it is of course possible to receive them separately.

FIG. 8 shows another embodiment of the suction pipe 20.
Here, in order to lay the four suction pipes 20, instead of laying the check valves 21 in each of the suction pipes 20, a collecting pipe 22 that connects these suction pipes 20 is provided, and its proximal end portion 1 is provided with one check valve 21 and then connected to the flow path section 6.
By doing in this way, one check valve 21 is sufficient, and cost reduction can be aimed at.

  The apparatus of the present invention can be applied to all castings using a disappearance model, and its application range is wide.

It is a general | schematic side view of the whole 1 process state of the vanishing model casting apparatus concerning this invention. It is a general | schematic side view of the whole 1 process state of the vanishing model casting apparatus concerning this invention. It is a perspective view of the state where the extended band of the cast frame of the disappearance model casting device concerning the present invention was laid. It is a top view of the state which removed the band of the cast frame of the vanishing model casting apparatus concerning the present invention. It is a partially cutaway front view of the suction pipe of the vanishing model casting apparatus according to the present invention. It is a graph which shows the experimental example concerning the vanishing model casting apparatus concerning this invention. It is a graph which shows the experimental example concerning the vanishing model casting apparatus concerning a prior art. It is a perspective view which shows another aspect of the suction pipe of the vanishing model casting apparatus concerning this invention. It is a general | schematic side view of the whole 1 process state of the vanishing model casting apparatus which shows a prior art. It is a general | schematic side view of the whole 1 process state of the vanishing model casting apparatus which shows a prior art. It is a perspective view in the state where the band of the cast frame of the disappearance model casting device showing the prior art was placed. It is a general | schematic longitudinal cross-sectional side view which shows the open frame method for the vanishing model casting concerning a prior art.

Explanation of symbols

1: Casting frame 2: Casting sand 3: Disappearance model 6: Channel portion 10: Pressure reducing means 14: Air supply means 20: Suction pipe 20a: Suction port 21: Check valve 22: Collecting pipe

Claims (5)

The vanishing model is installed in the casting frame, and a flow path portion having a flow path function is provided at the lower part of the casting frame to form an air flow path, and a pressure reducing means is connected to the air flow path, The casting frame is depressurized to suck the generated gas and strengthen the consolidation of the casting sand in the casting frame, and an air supply means for injecting compressed air into the flow path portion is continuously provided. A vanishing model casting device configured to stir and flow sand,
At least one suction pipe is connected upward from the flow path portion, and a plurality of suction holes are perforated at predetermined positions in the axial direction of the suction pipe, and
A check valve that prevents the compressed air from being pressed into the suction pipe from the flow path portion by the air supply means, and allows the gas to be sucked and discharged from the suction pipe through the flow path portion by the decompression means; Provided,
A vanishing model casting apparatus characterized by that.   The vanishing model casting apparatus according to claim 1, wherein the check valve is provided in the vicinity of the lower end of the suction pipe.   A plurality of the suction pipes are provided, these suction pipes are connected to the flow path portion via a collecting pipe, and one check valve is provided in the collecting pipe. 1 disappearance model casting device.   The vanishing model casting apparatus according to any one of claims 1 to 4, wherein the suction pipes are respectively arranged in the vicinity of the four corners of the casting frame.   The vanishing model casting apparatus according to claim 1, wherein at least the suction port of the suction pipe is covered with a mesh.

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