JPH0787982B2 - Discharge control device for metal hot water furnace - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a discharge control device for a metal hot water furnace that supplies a molten metal such as an aluminum alloy to a die casting machine or the like.

(Prior art and its problems) As a metal water heating furnace of this type, the Japanese Patent Publication No.
There are known ones described in Japanese Patent Publication No. JP-A No. 2004-242, and those described in PCT-EP84-192 of the international application.

However, in the former hot water supply furnace, the molten metal is pressure-fed from the discharge port of the holding chamber by sending the compressed gas into the holding chamber that stores the molten metal, so the pressure in the relatively large space inside the holding chamber rises. However, there are disadvantages that the compressed gas supply device becomes large and good accuracy cannot be obtained.

On the other hand, in the latter case of the hot water supply furnace, a pressure chamber is separately provided at the bottom or lower side of the holding chamber, the molten metal is supplied from the holding chamber, and the molten gas is discharged from the pressure chamber by sending compressed gas into the pressure chamber. Since it is configured to feed the compressed gas from the outlet, the compressed gas supply device can be downsized. FIG. 4 is a vertical cross-sectional view showing the schematic structure of this hot water supply furnace.
The pressure chamber 2 and the pressure chamber 2 are partitioned by a partition wall 3, and the holding chamber 1
A replenishment passage 4 for replenishing the molten metal from the holding chamber 1 to the pressure chamber 2 is formed at a predetermined portion of the partition wall 3 corresponding to the bottom of the. A tubular plunger 5 is provided in this supply path 4,
The supply path 4 is opened when the plunger 5 moves upward, and closed when the plunger 5 moves downward. The conduit 5a in the plunger 5 can be switched and connected to a gas supply source such as nitrogen gas and the atmosphere through an air supply valve and an exhaust valve (not shown). Then, in this hot water supply furnace, the molten metal 10 stored in the holding chamber 1 is released by the upward movement of the plunger 5 while maintaining an appropriate temperature from the pouring port 6 through the filling chamber 7, the soaking chamber 8 and the heater 9. Supply route 4
After that, the pressure chamber 2 is filled with the gas, and accordingly, the gas in the pressure chamber 2 is discharged to the outside air through the conduit 5a of the plunger 5. Next, when the supply passage 4 is closed by the downward movement of the plunger 5, a compressed gas having a predetermined pressure is supplied into the pressure chamber 2 through the conduit 5a of the plunger 5, and the pressure gas is pushed by the compressed gas to generate pressure in the pressure chamber 2. The molten metal 10 therein is supplied from a rising pipe 11 communicating with the pressure chamber 2 to a hopper 13 of a die casting machine via a discharge port 12. The amount of molten metal supplied is controlled to a constant amount each time by controlling the supply time with a timer or the like while keeping the pressure of the compressed gas supplied to the pressure chamber 2 at a predetermined pressure with a pressure regulator. When the supply of the molten metal 10 is completed, the plunger 5 moves up again and the same operation as described above is repeated.

However, in the case of discharge control in this hot water supply furnace, the amount of compressed gas supplied to the pressure chamber 2 in each molten metal supply is a constant amount that is controlled by time, and therefore, depending on fluctuations in the amount of molten metal in the holding chamber 1. However, there is a problem in that the amount of molten metal supplied each time varies slightly. This is because the liquid level of the molten metal 10 in the rising pipe 11 before supplying the molten metal is at the same level as the liquid level of the molten metal 10 in the holding chamber 1, and the level fluctuates according to the increase or decrease of the molten metal 10 in the holding chamber 1. is there. That is, when the liquid level of the molten metal 10 in the rising pipe 11 is lower than the standard, for example, unless the amount of compressed gas supplied to the pressure chamber 2 is increased by that much, the molten metal supply amount will not be constant each time, but the holding chamber It is practically not easy to accurately control the supply amount (that is, the supply time) of the compressed gas in accordance with the change in the molten metal amount in No. 1, and a precision control system is required.

(Object of the Invention) The present invention has been made to solve the above-mentioned problems of the prior art, and does not use complicated control means, and does not depend on the increase or decrease in the amount of molten metal in the holding chamber, etc. An object of the present invention is to provide a discharge control device for a metal hot water supply furnace, which is capable of supplying good molten metal.

(Means for Achieving the Object) In order to achieve the above object, the present invention provides a holding chamber for storing molten metal and a pressure which is provided separately from the holding chamber and is supplied from the holding chamber through a replenishing passage. A metal hot water supply unit provided with a chamber and a pipe line connecting the pressure chamber and a gas supply source, and the molten metal in the pressure chamber is delivered from the discharge port of the pressure chamber by the pressure of the compressed gas supplied from the pipe line. In the discharge control device of the furnace, connected to an air supply valve provided in the middle of the above-mentioned pipe line and a pipe line on the downstream side of this air supply valve and driven to advance when the air supply valve is closed Cylinder for sending the gas in the pressure chamber to the pressure chamber, a level sensor disposed facing the discharge port of the pressure chamber for detecting that the molten metal surface at the discharge port reaches a predetermined level, and moving the cylinder back and forth. And a cylinder driving means for driving. The advancement drive of the cylinder by the cylinder drive means is composed of a preload stroke drive until the level sensor detects the molten metal surface, and a constant stroke drive thereafter. That is, first, the cylinder driving means applies a cylinder advance drive (preload stroke drive) to apply a preload to the pressure chamber until the level of the molten metal at the discharge port of the pressure chamber reaches a level detected by the level sensor. The level of the molten metal is set to a constant level, and then the cylinder drive means further drives the cylinder to advance by a predetermined stroke amount (constant slot talk drive) so that the amount of molten metal supplied each time is a constant amount corresponding to the constant stroke. Is configured to be.

(Embodiment) FIG. 1 is a schematic view of an entire metal water heating furnace to which a discharge control device according to an embodiment of the present invention is applied, and FIG. 2 is a sectional view taken along the line AA of FIG. Indicates.

The main body side of this metal water heating furnace is PCT-EP8 of the international application mentioned above.
The molten metal 16 has a structure similar to that of the conventional example described in No. 4-192, and is supplied from the pouring port 14 and kept at an appropriate temperature by the heater 15.
A pressure chamber 19 that is partitioned from the holding chamber 17 via a partition wall 18 is provided below the holding chamber 17 that stores the liquid, and a pressure chamber for the molten metal 16 in the holding chamber 17 via a supply passage 20 formed in the partition wall 18. Configured to replenish to 19. The supply passage 20 is closed by a cock type plug 21 as shown in FIG. 2, and the supply passage 20 can be opened by rotating the plug 21 by a predetermined amount.

The discharge port 23, which is the outlet of the rising pipe 22 communicating with the pressure chamber 19, has an open upper side, and a level sensor 24 for detecting that the liquid level of the molten metal 16 at the discharge port 23 reaches a predetermined level L _b. , So that it can be raised and lowered by the air cylinder 25,
It is arranged so as to face the discharge port 23. Above level sensor 24
As such, a temperature sensor having a small heat capacity such as a semiconductor temperature sensor is used here.

Further, the supply / exhaust pipe 26 communicating with the pressure chamber 19 is connected to the discharge control device 27.
An exhaust electromagnetic valve 29 is provided in the middle of an exhaust pipe line 28b connected to the pipe line 28 and opened to the outside air. Gas cylinder that is the gas supply source in the above pipeline 28
In the middle of the air supply line 28a connected to 30, the air supply valve 31
Is provided, and the air supply line 28 upstream of the air supply valve 31 is provided.
In a, a stop valve 32, a regulator 33, and a charge tank 34 are sequentially provided from the gas cylinder 30 side. The internal pressure of the charge tank 34 is set slightly higher than the atmospheric pressure.

On the other hand, a cylinder 35 is connected to the downstream side of the air supply valve 31 in the air supply pipe 28a, and the cylinder 35 is configured to be driven back and forth by a slide shaft 36 which is a cylinder drive means. The stroke of the slide shaft 36 is controlled by a detection signal of the level sensor 24 and an encoder 37 attached to the slide shaft 36. That is, the advance / retreat stroke is a preload stroke until the level sensor 24 outputs a detection signal (corresponding to a portion between a and b indicated by the cylinder 35) and a predetermined stroke (cylinder) set by the encoder 37. (Corresponding to the code b-c shown in 35)
It is supposed to be given as the sum of and.

An electromagnetic valve 40 is provided on the downstream side of the connection point of the air supply pipeline 28a with the cylinder 35, and the downstream side thereof is connected to the charge tank 34 via a recovery pipeline 28c. A recovery valve 38 and a filter 39 are provided in the middle of the recovery pipeline 28c so that a part of the compressed gas sent to the pressure chamber 19 can be recovered from the recovery pipeline 28c to the charge tank 34. Has been done. The solenoid valve 40 described above is used for switching between a compressed gas supply operation and a recovery operation. In FIG. 1, 41 is a pressure gauge for monitoring the internal pressure of the charge tank 34, and 42 is a ventilator of the cylinder 35.

Next, the operation of the discharge control device 27 of the metal hot water furnace will be described with reference to the flowchart shown in FIG.

With the molten metal 16 being replenished from the holding chamber 17 side through the replenishment passage 20 into the pressure chamber 19, the molten metal level at the discharge port 23 is at level L _{a as} shown in FIG. Both valve 31 and recovery valve 38 are closed, and solenoid valve 29 is closed.
40 is open.

From this state, the movement (preload stroke drive) of the slide shaft 36 shown in step S ₁ in FIG. 3 is started, and the cylinder 35 is driven to advance from the standby position indicated by the symbol a. With this operation, the pressure chamber 19 is pressurized and the discharge port 23
When the level of the molten metal at the level rises to the level L _b , the level sensor 24 detects this as shown in step S ₂ in FIG. 3, and the movement of the slide shaft 36 is stopped in response to the detection signal, and the cylinder 35 Stops at the detection position indicated by the symbol b. At the same time, the air cylinder 25 operates and the level sensor 24
Is raised above the discharge port 23 to protect it, while the output count value (for example, counted by a counter (not shown)) of the encoder 37 attached to the slide shaft 36 is reset to “0” and not shown. the standby state of step S ₃ to wait for hot water supply instruction from the die casting machine.

From this state, the transition to step S _4, which is given hot water supply instruction by die machine metal hot water furnace side, the slide shaft 36 starts moving (constant stroke drive) again,
As a result, in step S ₅ , tapping is started. That is, the pressure chamber 19 passes through the air supply line 28a and the air supply / exhaust pipe 26.
The molten gas 16 is discharged from the discharge port 23 by the compressed gas pumped in and is supplied to the hopper (not shown) of the die casting machine. At this time, the movement amount of the slide shaft 36 is encoded by the encoder 37 and counted. On the other hand, a count value indicating a constant stroke amount corresponding to the hot water supply amount is preset, and when the cylinder 35 advances from the previous stop position b to the position indicated by the symbol c corresponding to the constant stroke amount, the encoder 37 Has reached the preset count value, and in response thereto, the advance drive of the slide shaft 36 is stopped.
In this way, a certain amount of molten metal 16 corresponding to the amount of advance from the position b to the position c of the cylinder 35 is discharged from the discharge port 23 and supplied to the hopper of a die casting machine (not shown).

After completing step S ₆ of the pouring by the operation described above, while the recovery valve 38 in step S ₇ is opened, is closed solenoid valve 40 is a part of the compressed gas downstream of the supply duct 28a by this Is collected in the charge tank 34 from the collection pipe 28c through the filter 39, and gas is saved. At this time, the powder contained in the collected gas is removed by the filter 39. Further, since the regulator 33 constantly applies a slightly higher internal pressure than the atmospheric pressure to the charge tank 34, this prevents the molten metal from excessively rising in the supply / exhaust pipe 26 during gas recovery. .

In this After step S _8, the recovery valve 38 is closed with the air supply valve 31 is opened, the slide shaft
36 reverse movements are performed. By this operation, the cylinder
35 is returned from the position c to the original position a while receiving the gas supply from the charge tank 34. This allows the air supply line 28
The internal pressure is slightly higher than atmospheric pressure on the downstream side of a.

Next, the air supply valve 31 is closed and the solenoid valve 29 is opened to replenish the pressure chamber 19 with the molten metal 16 in step S ₉ . This operation is performed by rotating the plug 21 shown in FIG. 2 by a predetermined amount to open the supply passage 20 of the partition wall 18, and the gas in the pressure chamber 19 is released from the exhaust pipe 28b to the atmosphere. Is discharged to.

When a predetermined replenishment time has elapsed, the plug 21 is returned to its original rotational position, replenishment path 20 is closed, the completion of the molten metal supply shown in step S _10. After this, the solenoid valve 29 is closed,
By opening the solenoid valve 40 and lowering the level sensor 24 to the reference height, and returning to the execution of step S ₁ ,
The same cycle is repeated thereafter.

(Effects of the Invention) As described above, according to the discharge control device for a metal hot water furnace of the present invention, the level of the molten metal at the discharge port is once adjusted to a reference level, and then the pressure chamber is moved by a predetermined amount. Since the compressed gas is sent to the hot water, hot water can always be supplied with high accuracy without using a complicated control mechanism. Therefore, there was almost no error in the discharge volume due to the increase or decrease in the amount of hot water supplied in the holding chamber, and it was possible to suppress the difference in discharge volume each time to about ± 0.1%. Further, since the structure thereof is a simple one that does not require a measurement timer or a pressure regulator, it is possible to obtain an effect that the pressure control during hot water supply becomes extremely easy.

[Brief description of drawings]

FIG. 1 is a schematic view of an entire metal water heating furnace to which a discharge control device according to an embodiment of the present invention is applied, FIG. 2 is a sectional view taken along the line AA of FIG. 1, and FIG. FIG. 4 is a flowchart showing the operation, and FIG. 4 is a vertical sectional view of a conventional example. 16 ... Molten metal, 17 ... Holding chamber, 19 ... Pressure chamber, 20 ... Supply channel, 23 ... Discharge port, 24 ... Level sensor, 28 ... Pipeline, 30 ... Gas cylinder (gas supply source) , 31 …… Air supply valve, 35 …… Cylinder, 36 …… Slide shaft (cylinder drive means)

Claims (2)

[Claims] Claim: What is claimed is: 1. A holding chamber for storing molten metal, a pressure chamber provided separately from the holding chamber, for supplying molten metal from the holding chamber via a replenishing passage, and a pipe connecting the pressure chamber and a gas supply source. In a metal water heating furnace, which is configured to deliver the molten metal in the pressure chamber from the discharge port of the pressure chamber by the pressure of the compressed gas supplied from this pipe, an air supply valve provided in the middle of the pipe. A cylinder that is connected to a pipeline on the downstream side of the air supply valve, is driven to advance when the air supply valve is closed, and pumps gas in the downstream pipeline to the pressure chamber; and a discharge port of the pressure chamber. The cylinder drive means includes a level sensor that is disposed to face the cylinder and that detects when the level of the molten metal at the discharge port reaches a predetermined level, and a cylinder drive means that drives the cylinder back and forth. Is the level sensor A discharge control device for a metal hot water supply furnace, which comprises a pre-load stroke drive until the molten metal surface is detected and a constant stroke drive thereafter. 2. A gas recovery charge tank, which is kept at a pressure slightly higher than atmospheric pressure, is provided in the pipeline in the upstream side of the air supply valve, and the charge tank and the gas supply valve are provided downstream of the charge tank. The discharge control device for a metal hot water supply furnace according to claim 1, wherein the discharge control device is in communication with the side pipe via a recovery valve.