JPH0642986B2 - Hot water pump for molten metal - Google Patents

Description

TECHNICAL FIELD The present invention relates to a molten metal hot water supply pump, and more particularly to a molten metal hot water supply pump suitable for filling a molten metal into a mold by pressure operation.

[Conventional technology]

A hot water supply pump is used to supply a molten metal such as aluminum to a die casting machine such as a vertical casting machine or a horizontal casting machine, a holding furnace or the like.

For example, the one applied to a vertical low-pressure casting machine is disclosed in JP-A-57-
No. 19148, a furnace filled with molten metal and a mold are connected by a molten metal supply furnace, an electromagnetic pump is installed in this molten metal supply furnace, and the mold is pressurized and filled by the pressure in the furnace. It is configured to be performed by an electromagnetic pump.

However, in such a configuration, the method of adjusting and measuring the molten metal delivery speed or delivery amount becomes complicated,
The hot water supply control cannot be performed accurately. This problem also occurs when the molten metal is sent out by air pressure in a closed melting furnace instead of using the electromagnetic pump.

As a solution to this problem, the applicant previously proposed the hot water supply system shown in FIG.

In FIG. 5, a melting furnace 1 is filled with a molten metal, and a crucible-less type is used. The melting furnace 1 is provided with a valve 2 for shutting off hot water discharge to the mold in an emergency, and the valve 2 is controlled by an air cylinder 3. Further, a melting surface sensor 4 is installed in the melting furnace 1 in order to detect the level of the melting surface in the furnace.

A transfer furnace 5 is connected to the valve 2, and a pump device 6 for supplying hot water is connected to the other end as a non-compressible molten metal transfer means.
The pump device 6 includes a plunger 7 for pumping the molten metal from the transfer path 5 to a mold, a cylinder 8 fitted on the plunger 7, a hydraulic cylinder 9 for reciprocating the plunger 7 in the cylinder 8, and the hydraulic pressure. It is composed of a plunger pump system 10 which is a drive source of the cylinder 9.

A runner pipe 11 is arranged on the output side of the pump device 6 with an inclination, and a mold 20 is connected to the upper end of the runner pipe 11. A protective cover 12 made of a heat-resistant material such as ceramic is attached to the outer peripheral portion of the runner pipe 11 in order to prevent the temperature of the molten metal from decreasing, and a heat retaining heater 13 is provided in the cover 12.

The mold 20 is composed of a fixed mold 21 and a moving mold 22,
A sprue 23 is arranged between the fixed mold 21 and the outlet of the runner pipe 11.

In the above configuration, the plunger pump system 10
Is controlled by a hot water supply program determined in advance according to the shape of the mold 20.

The plunger 7 in the initial state is on the ascending side and connects the transport path 5 and the runner pipe 11 to each other. Therefore, the molten metal is filled to the height in the runner pipe 11 at the same level as the molten metal level in the melting furnace 1.

With the movable mold 22 set in the fixed mold 21, the plunger pump system 10 is driven to move the plunger 7
When is lowered by a predetermined amount, the molten metal immediately below the plunger is pressed, and the molten metal level in the runner pipe 11 rises. This plunge 7 descends until the surface reaches the sprue 23.
It is done at high speed.

Next, while the plunger 7 is lowered stepwise, the molten metal is filled according to the cavity shape. After the mold 20 is completely filled with the molten metal, a certain high molten metal pressure is applied, and when the product is cooled, the plunger 7 is raised to restore the molten metal.

[Problems to be solved by the invention]

However, for the hot water supply pump having the configuration shown in FIG.
A crucible-less melting furnace is required and cannot be applied to general crucible furnaces. Further, although it is necessary to use ceramics or the like for the runner pipe 11, there is a problem in that it is difficult to increase the diameter and is easily damaged. Furthermore, the level of the molten metal in the runner pipe may move up and down significantly together with the level of the molten metal in the melting furnace, causing air entrapment in the runner pipe, making it difficult to obtain a high-quality cast product.

Further, conventionally, an automatic water heater as described in Japanese Utility Model Laid-Open No. 50-50809 has been proposed.

This device has one discharge port in the piston body, and a groove is formed on the side surface of the valve rod that opens and closes the discharge port at the lower end,
The discharge port is connected to a hot water supply pipe.

When the discharge port is closed by this valve rod, the inside of the furnace communicates with the inside of the piston body by the groove, and when the piston is raised, the molten metal in the furnace passes through the groove and is filled inside the piston body.

After that, when the valve rod is raised and the discharge port is opened, the lower part of the groove is blocked by a part of the piston body and the communication between the inside of the furnace and the inside of the piston body is cut off, and by lowering the piston, inside the piston body The mechanism is such that the molten metal is guided to the hot water supply pipe through the discharge port.

But with this piston pump: A groove for suctioning hot water is formed on the side surface of the valve rod, and when the valve rod has a small diameter, the groove width is inevitably narrow and the flow resistance of the molten metal in the groove becomes large, which requires a large piston pulling power. Therefore, the running cost is high.

． If the diameter of the valve rod is increased, the groove width becomes wider, but the weight of the valve rod becomes heavier, and a large amount of power is required to pull up the valve rod, resulting in high running cost.

． Since one valve rod switches between suction and discharge of hot water, the discharge port is partially opened while the valve rod is being pulled up, and the groove communicates the inside of the furnace with the inside of the piston body. There are times when.

The discharge port has a high flow resistance of the molten metal because it is connected to the slender hot water supply pipe, but the groove has a lower flow resistance than the discharge port side because it is open to the furnace. Therefore, when the piston is pushed down in the above-mentioned state, a part of the molten metal passes through the groove and is discharged into the furnace.

When a part of the molten metal to be supplied is discharged into the furnace in this way, not only a certain amount of molten metal is not supplied to the hot water supply pipe side, but also the tip of the hot water supply pipe is directly connected to the mold. The equipment has a great influence on the quality of the casting.

That is, if a certain amount of molten metal is not sent to the hot water supply pipe, the level of the molten metal in the hot water supply pipe is lowered, so that air invades from the vicinity of the tip of the hot water supply pipe and entrains air during casting.

Further, if a certain amount of molten metal is not fed, the molten metal pressure in the mold will be lowered, and the transferability will be adversely affected, which will have a serious adverse effect on the quality.

It should be noted that although the discharge port is also opened and the groove communicates the inside of the furnace with the inside of the piston body for an extremely short time, the discharge pressure of the piston is so high that the molten metal is discharged into the furnace.

The object of the present invention is to eliminate such drawbacks of the prior art,
It is an object of the present invention to provide a molten metal pump that is easy to manufacture regardless of the type of the molten metal furnace and that can obtain a cast product with stable quality without causing a level change.

[Means for solving problems]

In order to achieve the above object, the present invention provides a piston operable from the outside of the furnace, a cylinder tube into which the piston is reciprocally movable, and a bottom chamber at the lower end of the cylinder tube. And a bottom flange provided with a molten metal outlet, an inlet valve that opens and closes the molten metal inlet in conjunction with operation of the piston, and communicates the bottom chamber with a melting furnace, and communicates with the molten metal outlet and an upper part. A rising pipe having a branch port formed therein, a discharge valve that opens and closes the branch port by operating the piston, and a hot water conduit pipe having one end connected to the branch port and the other end connected to a mold. There is.

And the lower part of the cylinder tube, the bottom flange,
By immersing a part of the suction valve and the lower part of the rising pipe in the melting furnace, the molten metal introduction port is opened and closed by the suction valve and the branch port is opened and closed by the discharge valve as the piston reciprocates. It is characterized in that the hot water is directly supplied to the mold through the hot water conduit.

[Action]

The hot water pump configured as described above closes the branch port,
Hot water is introduced into the cylinder tube by opening the molten metal inlet and pulling up the piston, closing the molten metal inlet, opening the branch port, and pushing down the piston to supply the molten metal in the cylinder tube into the mold. it can.
Therefore, not only the melting furnace without a crucible shown in FIG. 5 but also a general crucible furnace can be applied.

Further, since the molten metal inlet and the branch port are provided separately, and the molten metal can be sucked and discharged individually by the suction valve and the discharge valve, the molten metal can be sucked in without increasing the power cost unlike the conventionally proposed one. The discharging operation is performed smoothly.

Furthermore, since the molten metal can be inhaled and discharged separately, the molten metal level in the molten metal pipe does not drop, the molten metal pipe is always filled with molten metal, and there is no entrapment of air in the casting due to air intrusion. Since a predetermined molten metal pressure can be obtained, a good quality cast product can be manufactured.

〔Example〕

 An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a cross-sectional view of a molten metal hot water supply pump and a mold for receiving hot water in an embodiment of the present invention. In FIG. 1, since the same mold as the mold 20 shown in FIG. 5 is used, duplicated description will be omitted.

A hot water supply pump 40 according to the present invention is disposed in the melting furnace 30 (or a crucible) so as to be freely dipped therein, and is connected to the mold 20 by a flexible runner pipe 35.

The hot water supply pump 40 has a piston 41 that can be operated outside the furnace.
And a cylinder tube 42 into which the piston 41 is vertically movably fitted. The cylinder tube 42 is supported by bolts by a top flange 43 and a bottom flange 44. A bottom chamber 45 is formed in the bottom flange 44, and an inlet port 46 and a molten metal discharge port 54 are provided so that the bottom chamber 45 and the melting furnace 30 can communicate with each other. A valve seat 47 is formed at the introduction port 46, and a suction valve 48 whose tip shape matches the shape of the valve seat 47 is arranged so that the introduction port 46 can be opened and closed. The upper portion of the suction valve 48 is slidably attached to the top flange 43.
Is supported by.

The bottom flange 44 is further connected to the bottom chamber 45, and a rising pipe 49 is connected to the molten metal discharge port 54, and a branch port 50 is provided on the upper portion thereof to connect the runner pipe 35. The upper end of the rising pipe 49 is supported by the top flange 43, a valve seat 51 is provided in the pipe, and a discharge valve 52 for opening and closing the branch port 50 is inserted to this position. Like the suction valve 48, the discharge valve 52 can be moved up and down from outside the furnace.

The hot water supply pump 40 having the above configuration is immersed in the molten metal 53 in the melting furnace 30 in a state of being suspended by a crane or the like.

Next, the operation of the configuration of FIG. 1 will be described with reference to the operation explanatory diagrams of FIGS.

First, as shown in FIG. 2, the intake valve 48 is at the upper limit,
The piston 41 is at the lower limit, and the discharge valve 52 has the branch port 5
0 is closed.

From this state, when the piston 41 is gradually raised to the upper limit as shown in FIG. 3, the metal melt in the melting furnace 30 flows into the bottom chamber 45 from the inlet 46, and the cylinder tube 42 is filled with the metal melt 53. .

Next, as shown in FIG. 4, the suction valve 48 is lowered to close the introduction port 46, and the discharge valve 52 is raised to connect the runner pipe 35 and the rising pipe 49. When the piston 41 is pushed down in this state, the molten metal in the cylinder tube 42 flows out to the rising pipe 49 and is sent out to the runner pipe 35, and the mold 20
Is supplied to.

As described above, by providing the intake valve 48 and the discharge valve 52 and operating the piston 41, the rising pipe 49 can be always filled with the molten metal, so that the rising pipe 49 and the runner pipe 35 can be filled with air. Does not occur.

By using the ceramic in the portion in contact with the molten metal, heat retention can be improved and heat resistance can be improved.

〔The invention's effect〕

As described above, according to the present invention, since the electromagnetic pump or the like is not used, the structure is simple, and the amount of hot water discharged is proportional to the piston stroke, so that the amount of hot water discharged can be easily and reliably controlled. It is possible to reduce the cost. Further, since it is an immersion type, it can be used in both crucible furnaces and crucible-less furnaces.

Furthermore, since a molten metal inlet and a branch port are provided separately, and the molten metal can be sucked and discharged individually by the suction valve and the discharge valve, the molten metal can be sucked and discharged without increasing the power cost as conventionally proposed. The operation is performed smoothly.

In addition, since the molten metal can be sucked and discharged separately, the molten metal level in the molten metal pipe does not decrease, the molten metal pipe is always filled with molten metal, and there is no entrapment of air in the casting due to air intrusion. Since a predetermined molten metal pressure can be obtained, a good quality cast product can be manufactured.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention, FIGS. 2 to 4 are explanatory views for explaining the action of the hot water supply pump of the present invention, and FIG. 5 is a vertical low pressure using a conventional hot water supply system. It is sectional drawing which shows a casting machine. 20 ... Mold, 35 ... Runpipe, 40 ... Hot water pump,
41 ... Piston, 42 ... Cylinder tube, 43 ...
… Top flange, 44 …… Bottom flange, 45 ……
Bottom chamber, 46 ... Inlet, 48 ... Suction valve, 49 ...
Rise pipe, 50 ... Branch port, 52 ... Discharge valve, 54 ...
Molten metal outlet.

Claims (1)

[Claims] 1. A piston operable from the outside of the furnace, a cylinder tube into which the piston is reciprocally fitted, a bottom chamber is formed at the lower end of the cylinder tube, and a melt inlet and a melt outlet are provided. A bottom flange, a suction valve that opens and closes the molten metal inlet in association with the operation of the piston, and communicates the bottom chamber with the melting furnace; and a molten metal discharge port that forms a branch port in the upper part. A riser pipe, a discharge valve that opens and closes the branch port in conjunction with the operation of the piston, one end of the branch port, and the other end of a hot water conduit connected to a mold, the lower portion of the cylinder tube, The bottom flange, the lower part of the suction valve, and the lower part of the rising pipe are immersed in the melting furnace, and with the reciprocating movement of the piston, the inlet port opens and closes the molten metal inlet, and the discharge valve opens and closes the branch port. And by the hot water heater pump molten metal, characterized in that it is configured to hot water directly to the mold through the conduit.