JPS6092042A - Device for passing gas through casting mold - Google Patents

Abstract

PURPOSE:To cure surely a casting mold in short time with a min. rate of gas consumption by putting the molding sand packed therein with the molding sand curable by carbon dioxide into a hermetic chamber, sealing hermetically the chamber and evacuating the inside thereof to a vacuum then admitting gaseous CO2 into the chamber so that the gas is introduced to the central part of the molding sand. CONSTITUTION:A device 2 for housing casting molds is lowered A onto casting molds which are introduced by a conveyor 9, etc. into a hermetic chamber 1 and into which molding sand S curable by gaseous CO2 is packed to seal hermetically the molds. The inside of the hermetic chamber is sucked through a suction passage 6 to maintain a vacuum state therein. The gaseous CO2 is then admitted into the chamber through a supply passage 7 so that the gas is introduced to the center of the molding sand. The introducing of gas is stopped after gas curing and the device 2 is moved upward A. The molds are carried out by a conveyor 10. Since the gaseous CO2 is thoroughly filled to the central part of the molding sand, the sand is cured quickly and surely and working efficiency is considerably improved. The gas consumption is minimized.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved mold venting device for carrying out the carbon dioxide process (CO2 process).

In the carbon dioxide gas method, a special sodium silicate called CO2 set or Hycholine is generally mixed into silica sand.

In this mold manufacturing method, the silica sand is poured into a mold to form a sand mold, and then CO2 gas is blown in to harden the sand mold.

This method of manufacturing molds has the characteristics that the solidification time of the sand mold is relatively short, that a drying oven is not required, and that a mandrel is not required for the core because the bonding force of the molding sand is very large.

When carrying out the carbon dioxide method, it is necessary to uniformly harden the entire sand mold, so the sand mold is filled with carbon dioxide.
Various means are used to blow in O2 gas. For example, there is one in which the entire top surface of the sand mold is covered with a hood with a rubber gasket, and CO2 gas is allowed to flow into the hood. There is also a method in which a cap that is large enough to cover only a portion of the upper surface of the sand mold is moved one after another, and CO2 gas is allowed to flow into the cap. Furthermore, by inserting a ventilation needle with a large number of small holes into the sand mold and letting CO2 gas flow into the ventilation needle, CO2 is introduced into each part of the sand mold through the small holes.
There are devices that distribute two gases.

When forming a sand mold on a wooden mold, the wooden mold is made hollow and a large number of small holes are bored in the upper surface of the wooden mold, and the KCO2 gas inside the mold is allowed to flow into the small holes. Some devices distribute CO2 gas to different parts of the sand mold through holes.

As described above, two various means have been conventionally adopted for blowing in CO2 gas, and both of them have a pressure of 2 to 4 αt.

Since the method involves injecting CO2 gas having a gas pressure of Therefore, in order to reliably harden the entire sand mold, it was necessary to use a much larger amount of special sodium silicate and 002 gas mixed into the silica sand than the theoretical values. However, even if a large amount of CO2 gas or special sodium silicate is used,
This is because it is difficult to uniformly supply gas to the entire mold.

Unreacted parts may remain or overgutsing may occur.
There were cases where large variations in @type quality occurred. Furthermore, using a large amount of special sodium silicate not only increases production costs, but also causes problems such as mold sticking, burning, and gas defects, which affect the quality of the product, collapsibility during frame dismantling, sand regeneration, etc. It causes inconvenience to Z).

The object of the present invention is to be able to greatly reduce the amount of additives such as special sodium silicate to silica sand, the required CO2 gas gas, and the gas passage time of CO2 gas.

It is an object of the present invention to provide a gas supply device for a mold, which allows a conventionally used model to be used as is.

In order to achieve this object, the mold gas supply device of the present invention has the following configuration. That is, one end of the intake passage and one end of the CO2 gas supply passage are opened in the airtight chamber housing the @ type, the other end of the intake passage is connected to the intake device, and the other end of the CO2 gas supply passage is opened. Connect to CO2 gas supply device.

K for manufacturing a mold using the mold gas-passing device of the present invention having such a configuration is as follows. First, 0.5 to 4 parts of sodium silicate, potassium silicate, or a mixture thereof is mixed into a mold base material such as silica sand, zirco sand, or chromite sand, and a desired sand mold is formed using a model or the like. Perform mold filling. next.

This sand mold is housed in an airtight chamber together with the model, and the air intake device is operated to create a vacuum higher than 200 m+Hg in the airtight chamber. Then, while stopping the operation of the intake system,
Activate the CO2 gas supply device.

CO2 gas is introduced into the airtight chamber. by this.

The sand mold is cured.

Therefore, according to the mold gas passage device of the present invention, C0
2 gas is instantly supplied into a highly evacuated airtight chamber, and most of the supplied CO2 gas passes through the entire sand mold, compared to when CO2 gas is injected in the atmosphere. in a much shorter time and in smaller amounts
The sand mold can be hardened with an amount of 0.02 gas. Furthermore, since the supplied CO2 gas reliably passes through the entire sand mold, it is sufficient to mix a much smaller amount of sodium silicate or the like into the silica sand than in the past.

Two embodiments of the present invention will be described below with reference to the drawings.

1 and 2 show a first embodiment of the present invention.

This first embodiment relates to a gas venting device for molds for a wide variety of small quantities. A mold housing device 2 that constitutes an airtight chamber 1 inside is a main body 3.
It has a two-part structure including a fixed part 4 and a fixed part 4.

A lifting bar 5 is attached to the main body 3 and is linked to a cylinder device (not shown). The main body 3 has intake passages 6 and C.
The O2 gas supply passage 7 is connected, and these passages 6, 7
has one ends 6α, 7α open to the airtight chamber 1. A roller conveyor 8 is disposed at the bottom of the airtight chamber 1, and this roller conveyor 8 is disposed outside the mold storage device 2 and has the same height as the nine roller conveyors 9 and 10. In airtight room 1,
In addition, a baffle plate 11.1 is provided at a position facing the openings 6α and 7α.
A gasket 13 is provided at the joint between the main body 3 and the fixing portion 4. The gasket 13 may be attached to the main body 3 or to the fixing part 4.

A pulp 14 is interposed in the intake passage 6, and the other end of the intake passage 6 is connected to a vacuum tank 15.

Vacuum pump 1 via vacuum tank 15 pipe 16
7, and the vacuum pump 17 is driven by a motor 18. The exhaust pipe of the l9Vi vacuum pump 17 is shown. Here, an air intake device 20 is constituted by the pulp 14, the vacuum tank 15, the vacuum pump 17, and the motor 1B.

On the other hand, a pulp 21 is interposed in the CO2 gas supply passage 7, and the other end of the nine passage 7 is connected to a CO2 gas receiver tank 22. The CO2 gas receiver tank 22 is connected to the pipe line 23
I have Here, the pulp 21, the C02 gas receiver tank 22, the C02 gas generator 24, and the liquefied CO2 tank 2
6 and K constitute a CO2 gas supply device 27.

In FIG. 1, 28 and 29 indicate molds for forming a sand mold, and the mold 28 is moved over the roller conveyor 8.9 by C.
The mold 29 is taken in and taken out in the -C direction, and the mold 29 that has been cut is taken in and out in the B-B direction on the roller conveyors 8 and 10. Mold 2
8. 29, the main body 3 of the mold storage device 2
It is pulled up in the A direction by the lift bar 5.

The molding sand S to be placed in the mold 28 and 29 is prepared by adding 0.5 to 4 parts of sodium silicate, potassium silicate, or a mixture thereof to a mold base material such as silica sand, zircon sand, or chromite sand. configured.

The operation of the first embodiment will be explained below.

The molds 28 and 29 filled with mold sand S are placed on roller conveyors 9 and 1 while the main body 3 of the mold storage device 2 is raised.
0 from direction C and direction B, respectively. In this way, when the @ molds 28 and 29 are carried onto the roller conveyor 8, the two main bodies 3 descend in the A1 direction and are pressed against the fixing part 4, thereby forming the airtight chamber 1. At this time, the airtight state within the airtight chamber 1 is maintained reliably by the action of the packing 13.

Next, with the pulps 14 and 21 closed, the intake system [2(
1, and the pressure inside the Paquim tank 15 is increased to 200
Decrease below mH&. ] When the pressure inside the airtight tank 15 reaches the desired pressure, the nozzle 14 is opened and the airtight chamber 1 is closed.
Attract attention to others. The pressure inside airtight chamber 1 after evacuation is 20
It is desirable that it be 0 mHg or less. When the airtight chamber 1 is completely airtight, the pulp 14 is closed and the valve 21 is opened. When the pulp 21 is opened, the CO2 gas in the CO2 gas receiver tank 22 flows into the airtight chamber 1 due to the negative pressure in the airtight chamber 1, and hardens the mold sand S. After the mold sand S is hardened, the main body 3 of the mold storage device 2 is raised in the A direction, and the molds 28 and 29 are carried out in the c1 direction and the B direction, respectively.

FIGS. 3 and 4 show the main parts of a second embodiment of the present invention, and the feature of this embodiment is that the present invention is applied to a gas passage device for mass production of molds.

In this gas passing device, in order to improve mass productivity, a mold 31 is integrally formed inside a main body 30 of a mold accommodating device 2, and a gassing plate 32 covering the upper opening of the main body 30 and a main body 3
0 to form an airtight chamber 1. Gas vent holes 33, 33. ... are bored, and an intake passage 6 in which pulp 14 is interposed is connected to the main body 30. On the other hand, a gap CO2 gas supply passage 7 is connected. 34
teeth.

This is a gasket for ensuring airtightness between the main body 30 and the gashing plate 32.

How to make a sand mold using a gas passing device with such a configuration.

As shown in FIG.
1, and pours the casting sand S supplied from the blowing head 35 into the mold 31. Next, the gashing plate 32 is overturned on the second main body 30 to form an airtight chamber 1, and as in the case of the first embodiment, the airtight chamber 1 is evacuated and then CO2 gas is supplied to fill the casting sand S. Perform curing.

FIG. 5 shows the main part of a third embodiment of the present invention, and the feature of this embodiment is that the present invention is applied to a gas passage device for a large mold. In the gas passing device of this embodiment, the mold housing device 2 is composed of a base 37 having a gas passage 36 therein, and a flexible sheet 38. An intake passage 6 in which pulp 14 is interposed is connected to one end of the gas passage 36 of the base 37, and a pulp 21 is connected to the other end of the gas passage 36. Both ends of the gas passage 36 and the upper surface 37α are connected to the intervening plate 37. A large number of open ventilation holes 37h, 37h, . . . are formed. Therefore, the airtight chamber of the mold storage device 2 is formed by the space between the flexible sheet 38 and the upper surface 37α of the base 37, the numerous ventilation holes 37h, 37, and the gas passage 36.

In the gas passing device of this embodiment, the model 4o is arranged between the frames 39 erected on the upper surface 37α of the base 37, and the mold sand S is placed inside the frame 39.
supply. And frame 39. The 40° model sand S is airtightly covered with a flexible sheet 38, and the airtight chamber is airtight and C
(22 gas is supplied to harden the mold sand S.

As explained above, according to the mold gas supply device of the present invention, CO2 gas is highly evacuated and instantaneously supplied into the airtight chamber housing the mold, and the supplied CO2 gas is absorbed into the mold sand particles. Since the space between the tubes is evenly filled, compared to the case where CO2 gas is injected in the atmosphere, the time required for two passes is reduced to 2 to 2, and the amount of gas for two passes is reduced to 2 to 30 seconds.

Furthermore, since the CO2 gas is sucked into the space between the particles of the molding sand under negative pressure, there is no need to form holes for gas in the molding sand, greatly improving work efficiency. get.

In addition, since the CO2 gas is reliably sucked into the space where the mold sand particles are located under negative pressure, it is possible to perform uniform gutting even in deep, high areas, improving mold removal performance and mold quality. This has the effect of being able to achieve the following.

Since gas is passed uniformly and reliably over the entire molding sand, reliable curing can be achieved even if the amount of additives such as sodium silicate is reduced to less than the conventional Δ. Therefore, product defects such as burning and gas defects are less likely to occur, and the disintegration properties during unpacking are extremely good without the use of disintegrants.The degree of sand regeneration is also improved, and the amount of special sand used is This has the effect of reducing the

[Brief explanation of drawings]

FIG. 1 is a vertical sectional view of a main part of an embodiment of the present invention. FIG. 2 is a side view showing the overall configuration of the present invention. FIG. 3 is a longitudinal sectional view showing the operating state of a modified embodiment of the present invention. FIG. 4 is a longitudinal cross-sectional view of mold sand being hardened using the apparatus shown in FIG. FIG. 5 is a longitudinal sectional view of yet another modification of the invention. 1...Airtight room. 22.2... Mold storage device. 6... Intake passage. 7...CO2 gas supply passage. 14.21...War/Valve. 20... Intake device. 27...CO2 gas supply device. Patent applicant: Taiyo Steel Co., Ltd. (4 others)

Claims (3)

[Claims] (1) One end of the intake passage and CO2 in the airtight chamber housing the mold.
One end of the gas supply passage is opened, the other end of the intake passage is connected to an intake device, and the other end of the CO2 gas supply passage is connected to a CO2 gas supply device. gas equipment. (2) The intake device includes a valve interposed in the intake passage, and a vacuum tank connected to the other end of the intake passage. The @-type gas passing device according to claim 1, which comprises a vacuum pump connected to the vacuum tank and a motor for driving the vacuum pump. (3) The CO2 gas supply device W includes a pulp interposed in the CO2 gas supply passage, a CO2 gas receiver tank connected to the other end of the CO2 gas supply passage, and a CO2 gas receiver tank connected to the other end of the CO2 gas supply passage.
2. The mold gas passage device according to claim 1, comprising a CO2 gas generator connected to a 02 gas receiver tank, and a liquefied COZ tank connected to the CO2 gas generator.