JP3121251B2 - Pump for molten metal - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pump for molten metal used for aluminum die-casting and the like, and more particularly, to a cylinder, a piston which is vertically slidably fitted in the cylinder, and a piston between the cylinder and the piston. The present invention relates to a metal melt pump provided with a melt suction portion and a melt discharge portion that can communicate with a melt storage space.

[0002]

2. Description of the Related Art Conventionally, in a pump for molten metal,
Since the carrier fluid is at a high temperature, it is difficult to apply a normal metallic piston pump.To deal with this, in recent years, electromagnetic pumps and air pressurized pumps have been used. Several plunger pumps have been proposed to address control and maintenance issues. As an example of such a plunger pump, a ceramic plunger pump for aluminum die-casting having a plunger provided with a T-shaped molten metal inflow port at a lower end in a cylinder provided in a vertical position (for example, Japanese Patent Application Laid-Open No. 2-895
No. 49). In the plunger pump, molten aluminum is introduced into the upper portion of the cylinder. At the rising end position of the plunger, the molten aluminum is introduced into the cylinder from a horizontal portion to a vertical portion of the T-shaped molten metal inlet. It is configured to flow in and push out the molten metal in the cylinder by pushing down the plunger.

[0003]

In the above-mentioned conventional pump for molten metal, for example, in the case of an electromagnetic pump, the transport amount is controlled by the transport time, and the electromagnetic characteristics of the molten metal affect the transport capacity. At a constant pressure, it is difficult to reliably transport a constant amount, and in an air pressurized pump, although it can be pressurized and transported at a constant pressure,
In order to detect the transport amount, it is necessary to rely on a change in the level of the molten metal, and it is also difficult to reliably transport a constant amount. On the other hand, although the ceramic plunger pump can keep the internal volume of the cylinder constant and can control the injection pressure, the molten metal inlet serves as an on-off valve between the upper end of the cylinder and the molten metal inlet. In the initial stage of pushing down the plunger, the molten metal flows back into the molten metal inlet, and since there is no means for sucking molten metal in the cylinder, the plunger is raised. In such a case, the molten metal may be sucked in reverse from the injection pipe section that injects the molten metal from the cylinder. If the injection pipe section is provided with a check valve, a large pulling resistance occurs, and the check valve is provided. When there is no gas, since gas such as external air is sucked from the injection pipe portion, it is difficult to expect a smooth flow of the molten metal into the cylinder portion,
Further, there is a problem that outside air may be sucked and introduced into the injection pipe portion and the cylinder and come into contact with the molten metal, which may cause contamination such as oxidation of the molten metal. Therefore, an object of the present invention is to solve the above-mentioned problems, to provide a pump for a molten metal that can reliably inhale the molten metal and quantitatively transport the molten metal at a constant pressure while having heat resistance. To provide.

[0004]

[Function and effect of feature configuration]

Therefore, according to the above characteristic configuration, since the slide valve is provided in the piston shaft, the shape of the pump can be simplified, and the pump can be easily attached to the furnace lid of the heating furnace, and at the same time, During operation, the sliding valve provided in the piston which is always in contact with the molten metal can suppress a temperature change thereof, and accompanies a temperature change of each of the sliding valve as the sliding valve element and the piston as the valve body. Due to the difference in thermal expansion between the sliding valve element and the valve body that allows the sliding valve element to slide inside, it is possible to prevent malfunction of the sliding valve. further,
Since the flow path between the melt accommodating space and the outside can be switched, when the melt accommodating space expands along with the vertical sliding operation of the piston (that is, when the molten metal is sucked in), Since the state of the communication passage in the valve can be set to the first state, the molten metal can be reliably sucked into the molten metal storage space without resistance, and when the molten metal storage space is reduced (that is, at the time of molten metal injection). In this case, the state of the communication passage in the valve can be set to the second state, so that the molten metal can be reliably injected from the molten metal storage space. in short,
The piston operation force is effectively used for both the reciprocation of the sliding operation of the piston. As a result, it is possible to provide a pump for molten metal that has excellent heat resistance, is easy to handle, and can easily supply a fixed amount of pressure.

[Additional Configuration 1 and Functions and Effects] The molten metal storage space is formed on both sides of the piston in the sliding direction, and the communication passage in the valve is connected to the first molten metal storage space with respect to the first molten metal storage space. If it is formed so as to be switchable between the first state and the second state and to be switchable between the first state and the second state with respect to the other molten metal storage space (corresponding to claim 2). In this case, when the molten metal is injected from the one molten metal storage space, the molten metal can be simultaneously sucked into the other molten metal storage space. Also, while injecting the molten metal from the other molten space, the molten metal can be sucked into the one molten space, so that the molten metal can be continuously discharged with the reciprocating sliding of the piston. It becomes possible to inject. That is, a double-acting pump can be formed while being a pump for molten metal. As a result, for example, when injecting aluminum into a die-casting mold, it becomes possible to inject the molten metal with a small-sized pump for molten metal regardless of the volume of the mold. As a result, the cylinder inner diameter of the pump can be reduced, so that the operating force of the piston can be reduced.

[Additional Configuration 2 and Operation and Effect] Also, the intra-valve communication path in the additional configuration 1 can be switched between the first state and the second state with respect to the one molten metal storage space. And a second communication passage for switching between the first state and the second state with respect to the other molten metal storage space.
In this way, when injecting the molten metal from the one molten metal storage space,
Since the molten metal can be sucked into the other molten space, and the molten metal can be injected from the other molten space and the molten metal can be sucked into the one molten space even when the piston operates in the opposite direction, the pump Can be constituted as a double-acting pump, and the molten metal can be continuously injected as the piston reciprocates. As a result, for example, when injecting aluminum into a die-casting mold, it is possible to inject the molten metal with a small-sized pump for molten metal regardless of the volume of the mold. As a result, the cylinder inner diameter of the pump can be reduced, so that the operating force of the piston can be reduced.

[Additional Configuration 3 and Effects] The valve communication passage in the additional configuration 1 is connected to the first state with respect to the one molten metal storage space and the first state with respect to the other molten metal storage space. And a discharge communication passage which is switchable between the second state with respect to the one melt accommodation space and the second state with respect to the other melt accommodation space. In this case, as in the additional configuration 2, when the molten metal is injected from the one molten metal storage space, the other molten metal storage is simultaneously performed. The molten metal can be sucked into the space and the molten metal can be sucked into the one molten space while ejecting the molten metal from the other molten space even when the piston is operated in the opposite direction. It can be configured as a pump, and can continuously inject molten metal as the piston reciprocates. As a result, for example, when injecting aluminum into a die-casting mold, it is possible to inject the molten metal with a small-sized pump for molten metal regardless of the volume of the mold. As a result, the cylinder inner diameter of the pump can be reduced, so that the operating force of the piston can be reduced.

[Additional Configuration 4 and Functions and Effects] Further, the lower portion of the cylinder according to any one of the above-mentioned claims 1 to 4 is configured to be immersed in a molten metal, and an external portion is provided below the immersion liquid level of the cylinder. It is better if a through-hole communicating with the molten metal is provided, and the through-hole is disposed above the molten metal suction part and the molten metal discharge part (corresponding to claim 5). In this case, the molten metal suction part And the liquid level of the molten metal in the furnace outside the cylinder is located above the molten metal discharge section, so that the molten metal suction section and the molten metal discharge section are both kept warm by the molten metal in the furnace, Since the molten metal in the furnace, which communicates with the through hole, flows from above the partition that separates the molten metal suction portion or the molten metal discharge portion from the upper portion, if the piston shaft slides up and down, the molten metal is sucked. Part or the molten metal drain Even if the molten metal oozes out along the piston axis from the sliding part between the partition and the piston shaft that separates the outlet from the other part, the oozing metal melt flows into the furnace metal through the through-hole. And the molten metal is returned to the furnace, and at the same time, the partition wall is kept at the same temperature by the molten metal that has flowed in. Solidifies to prevent the piston shaft from sticking to the sliding portion, and prevent the sliding resistance between the piston shaft and the sliding shaft from increasing during vertical sliding operation. as a result,
Long-term stability of the operation of the metal melt pump can be ensured.

[Additional Configuration 5 and Functions and Effects] Further, an upper casing is provided which hermetically surrounds the upper part of the cylinder and the piston shaft extending above the cylinder according to any one of claims 1 to 5. It is even better if the upper casing is filled with an inert gas (corresponding to claim 6), so that the space above the cylinder is placed in an antioxidant atmosphere by the inert gas, As the piston shaft slides up and down, the molten metal oozes along the piston shaft from a sliding portion between the piston shaft and the partition that separates the melt suction portion or the melt discharge portion from other portions. Even if it does, the exuded molten metal can be prevented from being oxidized and solidified, and the piston shaft can be fixed to the sliding portion, or the piston shaft and the sliding shaft can be vertically moved. When Can be prevented from increasing. As a result, long-term stability of the operation of the metal melt pump can be ensured.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1 and 2 show a longitudinal section of an example of the aluminum metal casting pump for aluminum die casting of the present invention. FIG. 1 shows a state in which the piston 2 starts rising from the lower end of the pump P, and FIG.
Indicates a state in which the piston 2 starts to descend from the rising end. Note that the double arrow indicates the operation direction of the piston 2. The pump P is mounted on the furnace lid C by the mounting bracket 8a in the up and down posture, and a cylinder 1 made of silicon nitride provided with its lower part immersed under the surface S of the molten metal, and is fitted inside the cylinder 1 slidably up and down. as with the piston 2 made of silicon nitride, communicating Allowed the cylinder 1 and the molten metal receiving space 4 between the piston 2
It has a molten metal inlet 5 and a molten metal outlet 6. An upper casing 8 including the mounting bracket 8a is provided above the mounting bracket 8a, and a driving device 9 for the piston 2 is provided above the upper casing 8. The upper casing 8 is configured such that a cylindrical tubular portion 8b is hermetically attached to an upper portion of the mounting bracket 8a, and an upper lid portion 8c is hermetically attached to an upper end portion of the tubular portion 8b. A circular through hole is provided in the center of the mounting bracket 8a and the upper lid 8c. The driving device 9 is a double-acting cylinder device attached in the up-down direction, and has a driving piston 9a that is fitted and slid in the cylinder portion 9b. The driving device 9 has a lower end plate hermetically mounted on an upper portion of the upper casing 8. The molten metal discharge portion 6 is provided in the cylinder 1, and the annular space made of silicon nitride is attached to the cylinder 1 in a substantially sealed state between the cylinder 1 and the inner wall of the cylinder 1. Upper seal 6
b and an annular lower seal 6c also made of silicon nitride, and is formed between the upper seal 6b and the lower seal 6c.
Are fitted in a substantially sealed state between the inner wall of the cylinder 1 so as to be slidable up and down, so as to allow a slight leak of the molten metal from between the sliding surfaces. Specifically, the clearance between the sliding surfaces is set to 0.5 mm or less. Further, a cylindrical discharge portion spacer 11 made of ceramic is interposed between the upper seal 6b and the lower seal 1c, and is provided between the upper seal 6b and the lower seal 6c of the cylinder 1. Molten outlet 6
a is opened, and the outlet pipe 10a of the injection pipe section 10 for supplying the molten metal to, for example, a die-casting mold is hermetically attached. The discharge space 11 also has a discharge hole 11a penetrating therethrough communicating the inside thereof with the molten metal discharge port 6a. Further, an upper spacer 12, which is also made of ceramic and is inserted into the cylinder 1, is provided above the upper seal 6b. The upper spacer 12 is provided with a circular through hole of the mounting bracket 8a. The upper seal 6b is attached to the inner peripheral portion, and the upper seal 6b is positioned by the upper spacer 12. Further, the lower seal 6c is
Positioning is performed by the discharge part spacer 11 interposed between the upper seal 6b and the upper seal 6b. At the position corresponding to the lower surface of the lower seal 6c, a step is provided on the inner surface of the cylinder 1, and this step is formed on the contact surface with the lower seal 6c. In the pump P, each component is formed, the piston 2 and the lower seal 6c, the discharge spacer 11, the upper seal 6b, and the upper spacer 12 are sequentially inserted from above into the cylinder 1, and the lower seal is formed by the step. The structure is such that it can be easily and easily assembled by positioning and combining 6c. With this configuration, it is not necessary to subject each component made of a difficult-to-process ceramic material to processing such as a pin hole. Therefore, while using a ceramic material having a relatively high notch sensitivity, the durability is improved. The structure of a certain pump could be achieved. Further, the cylinder 1 has an upper end edge extending around the periphery in a flange shape.
The cylinder 1 is provided with a bottom plate 1c having a circular sliding hole formed in the center at the lower end of the operating portion 1a at the lower end of the cylinder 1 to isolate the space above the molten metal discharge portion 6 from the bottom. A melt accommodating space 4 is formed in the operating portion 1a between the lower seal 1c. A piston portion 2a of the piston 2 is vertically fitted inside the operating portion 1a so as to be vertically slidable. The molten metal accommodating space 4 is vertically divided by the piston portion 2a fitted into the cylinder 1. It is divided into a first molten metal storage space 4a below the piston portion 2a and a second molten metal storage space 4b above the piston portion 2a. A piston shaft 2b for vertically sliding the piston 2 is formed of a hollow tubular body, the piston shaft 2b extends below the piston portion 2a, and the bottom plate provided at the lower end of the cylinder 1 1c is vertically slidably fitted in the sliding hole of the extended piston shaft 2b and the sliding hole in a substantially sealed state so as to allow a slight leakage of the molten metal. ing.
Specifically, the clearance between the sliding surfaces is 0.5 mm
It is set as follows. Further, a slide valve 3 is provided in the piston shaft 2b so as to be vertically slidable therein, so that either one of the molten metal storage spaces 4a and 4b and the molten metal suction portion 5 are provided.
And the first molten metal storage space 4a, 4
The sliding valve 3 is provided with an in-valve communication passage 7 so as to be switchable to a second state in which any one of the b and the molten metal discharge portion 6 is communicated. The valve communication passage 7 is provided in the first molten metal storage space 4a.
And the second molten metal storage space 4b are alternately switched to the first state. The liquid absorption communication passage 7c, the first molten metal storage space 4a, and the second molten metal storage space 4b are alternately arranged. And a discharge communication passage 7d which can be switched to the second state. Specifically, a discharge hole for communicating the discharge communication passage 7d with the molten metal discharge portion 6 at the rising end and the falling end of the slide valve 3 is provided at a position of the piston shaft 2b in the molten metal discharge portion 6. A communication passage communicating with the first molten metal accommodating space 4a and communicating with the discharge communication passage 7d at the lower end of the slide valve 3; Melt storage space 4b
And a communication passage communicating with the discharge communication passage 7d at the rising end of the slide valve 3 is provided separately, and is further communicated with the second molten metal storage space 4b, and
At the lower end of the slide valve 3, the liquid suction communication passage 7c
And a communication passage communicating with the first molten metal accommodating space 4a and communicating with the liquid suction communication passage 7c at the rising end of the sliding valve 3 are separately provided. The sliding valve 3 is attached to an operating device including an air cylinder provided above a driving piston 9a of the driving device 9 by an operating shaft 3b.
Are connected to each other so that an up / down switching operation can be performed. The arrows in the figure indicate the flow direction of the molten metal. Further, as described above, the lower portion of the cylinder 1 is configured to be immersed in the molten metal in the furnace, and is located below the immersion liquid surface of the cylinder 1 and above the molten metal discharge portion 6, A through-hole 1b communicating with the outside is provided, and the upper spacer 12 is also provided with a through-hole 12a similarly to the through-hole 1b. An upper end of the piston shaft 2b extending above the cylinder 1 is connected to a driving piston 9a of the driving device 9 composed of a double-acting hydraulic cylinder (a hydraulic source, a control mechanism and the like are shown in the drawing). Is omitted), the upper part of the cylinder 1 and the extending piston shaft 2b are hermetically surrounded by the upper casing 8, and the upper casing 8 is filled with an inert gas. The ceramic pump P for molten metal shown as an embodiment of the present invention is configured as described above, and each sliding portion and each seal 6b, 6c located below the surface C of molten metal and the cylinder 1
It is a preferable configuration that the space between the inner wall and the inner wall is almost in a sealed state, and a structure that allows slight leakage of the molten metal is preferable, and the characteristics of ceramic are utilized to maximize the heat resistance and toughness. In addition, a dimensional error due to molding is allowed. This is why the through holes 1b and 12a are provided, and by flowing the molten metal in the furnace onto the upper seal 6b, a small amount of the molten metal leaks from the upper seal 6b due to the internal pressure. Even if it only mixes with the metal melt in the furnace, there is no problem. Further, by allowing a slight leak of the molten metal to each of the sliding portions, the molten metal can be provided with a lubricating effect between the sliding surfaces. Specifically, the bottom plate 1c is closer to the first melt storage space 4a, the lower seal 6c is closer to the second melt storage space 4b and the melt discharger 6, and the upper seal 6b is closer to the melt discharger 6. The edges of the sliding holes into which the piston shafts 2b are fitted are chamfered. In this way, the molten metal can easily enter between the piston shaft 2b and each of the sliding holes from the side where the molten metal is pressurized. As a result, a molten metal as a lubricant enters between these sliding surfaces to ensure smooth sliding. Further, by immersing the cylinder 1 together with the molten metal discharge section 6 and the like under the surface C of the molten metal in the furnace, it is possible to configure a metal molten metal pump P that can be easily handled without requiring a special heat retaining structure. It was. Further, since the upper casing 8 is provided and filled with an inert gas, the inside of the pump P can be prevented from oxidizing the high-temperature molten metal. Thus, it is possible to maintain a stable operation while maintaining the operation. Further, a sliding valve 3 is fitted in the piston 2 to allow the flow path of the molten metal
a and 4b are configured to be switchable between a first state communicating with the molten metal suction section 5 and a second state communicating with the molten metal discharge section 6 to form a double-acting pump. 10
The piston 2 can be driven to reciprocate while maintaining the injection pressure on the die, and can be handled by a miniaturized pump regardless of the size of the die casting mold.

Next, another embodiment of the present invention will be described. <1> The molten metal pump of the present invention is not limited to the above-described embodiment, and may be configured as a plunger-type piston pump. For example, FIG. Alternatively, a single-acting type may be configured to discharge the molten metal only when the plunger 2 is lowered. In the figure (A)
Indicates a rising state of the plunger 2 (a molten metal suction state),
(B) shows the plunger 2 in the lowered state (molten metal discharge state). In the molten metal suction state shown in FIG.
Is at the lower end, and the communication passage 7 in the valve is in a first state in which the melt accommodating space 4 is communicated with the melt suction portion 5 provided on the side of the cylinder 1, and as the plunger 2 rises, The molten metal flows into the molten metal storage space 4 via the communication passage 7 in the valve.
In the molten metal discharge state shown in (b),
The sliding valve 3 is at the rising end, and the communication passage 7 in the valve is a molten metal discharge portion 6 having a molten metal storage space 4 provided on a side portion of the cylinder 1.
(The connected injection pipe portion is not shown.) In the second state, the metal melt in the melt accommodating space is connected to the valve communication passage as the plunger 2 descends. 7, is injected under pressure from the molten metal discharge section 6. The space around the plunger 2 provided in the molten metal suction section 5 and the molten metal discharge section 6 corresponds to the plunger 2.
The relative rotation with respect to the cylinder 1 is allowed, but these surrounding spaces may be provided only in portions facing the molten metal suction section 5 and the molten metal discharge section 6, respectively. <2> As shown in FIG.
The sliding valve 3 may also be configured to slide and slide as conceptually shown in FIG. FIG. 4B shows a lowering state of the piston 2, and FIG. 4A shows a rising state of the piston 2. Figure
In the lowering operation state shown in FIG. 4 (b) , the slide valve 3 is brought into the second state in which the first molten metal accommodating space 4a is communicated with the molten metal discharge portion 6 provided on the side of the cylinder 1 and the second molten metal is contained. A communication passage is formed in a first state in which the space 4b communicates with a molten metal suction portion 5 provided on a side portion of the cylinder 1, and when the piston 2 is depressed, the communication passage is formed from the first molten metal storage space 4a. A first communication passage 7a provided in the sliding valve 3
The metal melt in the first molten metal storage space 4a is pressurized and injected from the molten metal discharge portion 6 through the second molten metal storage space 4b. At the same time, the second molten metal stored in the second molten metal storage space 4b is provided in the slide valve 3. The molten metal in the furnace is sucked from the molten metal suction section 5 through the communication passage 7b. 4A , the sliding valve 3 is in the first state with respect to the first molten metal storage space 4a and in the second state with respect to the second molten metal storage space 4b. A communication passage is formed in the state, and the molten metal in the second molten metal storage space 4b is press-injected from the second molten metal storage space 4b from the molten metal discharge portion 6 via the second communication passage 7b. At the same time, the first molten metal storage space 4
a, the molten metal in the furnace is sucked from the molten metal suction part 5 via the first communication passage 7a. In this arrangement, before Ki溶 water suction portion 5 also serves through holes 1b provided under the melt surface S of the cylinder 1 shown in the above embodiments. <3> The positional relationship between the molten metal storage space 4, the molten metal suction part 5, and the molten metal discharge part 6 is not limited to the arrangement in the above-described embodiment, and as shown in FIG. The space 4 may be provided with a molten metal inlet 5 and a molten metal outlet 6 thereon. Further, as shown in FIG. Molten drain at the top
The outlet portions 6 may be arranged, and the molten metal suction portion 5 may be arranged between them, or another arrangement may be adopted. <4> In the above-described embodiment, each of the liquid suction communication passages 7c and the discharge communication passage for switching the communication passages between the first and second molten metal storage spaces 4a and 4b inside the sliding valve body 3. Although the passage 7d is provided, the communication passages 7c and 7d may be individually provided for the respective molten metal storage spaces 4a and 4b. further,
As shown in FIG. 3, a single communication path may be used. In a plunger type piston pump, a liquid suction communication path 7 c and a discharge communication path 7 d are separately provided in the molten metal storage space 4. You may do so. <5> In the above-described embodiment, an example is shown in which the mounting bracket 8a is mounted on the upper end of the cylinder 1 and the piston pump P is mounted on the furnace lid C using the mounting bracket 8a. Optionally, it may be mounted by suspending it in the metal melt in the furnace using the injection tube section 10. Also, for example, as shown in FIG. 4, an upper end plate 1d is provided at the upper end of the cylinder 1 so that the piston shaft 2b is vertically slidable therein, and a hanging bracket is attached to the furnace lid C to suspend the cylinder 1. It is also possible to lower it and immerse it in the molten metal in the furnace. In this case, the operation mechanism of the driving device 9 and the sliding valve 3 may be attached to the furnace lid C. <6> In the above-described embodiment, the pump for aluminum die-casting has been described as an example. However, the piston pump of the present invention is not limited to the above-described application, and can be used for the purpose of fluid conveyance. It is suitable for conveying high-viscosity fluids or high-temperature fluids, and is particularly suitable for fixed-quantity supply. <7> In the above-described embodiment, silicon nitride having high compatibility with molten aluminum is used as the material of the cylinder 1 and the piston 2, and the material of the upper and lower seals 6b and 6c is made of ceramic. The same silicon nitride as the material of the piston 2 can be suitably used. Other ceramic materials can be used for the materials of these components, and if a ceramic material suitable for a carrier fluid, such as boron nitride, silicon carbide, alumina, a metal ceramic composite material, or a ceramic coated metal composite material, is selected. Good. In this case and when using the ceramic-metal composite material, the clearance provided in the sliding portion in the above-described embodiment of the present invention has a significant meaning. That is, the difference in dimensional change is absorbed by the clearance based on the temperature difference of the metal material having a larger thermal expansion coefficient than that of the ceramic, so that the sliding members can be prevented from coming into contact with each other and sticking. <8> In the above-described embodiment, an air cylinder is used as the driving device 9 as an example. However, any driving source may be used, and a hydraulic cylinder device, an electric device, or the like can be arbitrarily selected. <9> In the above embodiment, the piston 2
The opening of the communication passage for communicating the molten metal accommodating space 4 with the in-valve communication passage 7 in the sliding valve 3 opens to the molten metal accommodating space 4 so as to face the molten metal accommodating space 4 of the piston portion 2a. Although provided on the operating surface, it may be open to the piston shaft 2a. <10> In the above-described embodiment, the upper seal 6b and the lower seal 6c that divide the upper and lower portions of the molten metal discharge section 6 from other parts,
An outlet spacer 11 interposed between the upper and lower seals 6b and 6c and a molten metal outlet 6a opened in the cylinder 1.
However, the upper seal 6b, the lower seal 6c, and the discharge spacer 11 may be integrally formed.
May have a different shape, and may be a cylindrical body inscribed in the cylinder 1. Further, the molten metal suction part 5 or the molten metal discharge part 6 is different from the other embodiment <1>
As shown in FIG. 3, as shown in FIG. 3, a recess formed in the peripheral portion of the piston 2 and the molten metal inlet 5a or the molten metal outlet 6a may be used. <11> The cylinder 1, the piston 2, and the upper seal 6
a, the clearance between the sliding surfaces between the lower seal 6b and the lower seal 6b is an example suitable for a silicon nitride pump for molten aluminum in the above-described embodiment. It is not limited to the range, but is appropriately set according to the application and the constituent materials.

[0012]

As described above, according to the present invention,
It is possible to provide a pump for molten metal which has excellent heat resistance, is easy to handle, and can easily supply a fixed amount under pressure.

In the claims, reference numerals are provided for convenience of comparison with the drawings, but the present invention is not limited to the configuration shown in the attached drawings.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a rising operation state of a piston according to an example of an embodiment of the present invention.

FIG. 2 is a sectional view showing a lowering operation state of the piston in FIG. 1;

FIG. 3 is a conceptual diagram showing a main part of another embodiment of the present invention.

FIG. 4 is a conceptual diagram showing a main part of another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylinder 1b Through-hole provided in cylinder 2 Piston 2b Piston shaft 3 Sliding valve 4 Molten metal accommodating space 4a One molten metal accommodating space 4b The other molten metal accommodating space 5 Molten metal suction part 6 Molten metal discharge part 7 Valve communication path 7a First Communication path 7b Second communication path 7c Liquid absorption communication path 7d Discharge communication path 8 Upper casing C Furnace lid P Pump S Molten metal surface

────────────────────────────────────────────────── (5) References JP-A-2-89549 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B22D 17/02 B22D 17/30 B22D 39 / 00 F04B 15/04 F04B 53/12

Claims (6)

(57) [Claims] 1. A cylinder (1), to which a piston (2) fitted into vertically slidably, capable communicating with the cylinder (1) and said piston (2) molten metal receiving space (4) between A pump for molten metal comprising a molten metal suction section (5) and a molten metal discharge section (6), wherein a piston shaft (2) for vertically sliding the piston (2) is provided.
a first state in which a sliding valve (3) is provided inside b) to allow the molten metal storage space (4) to communicate with the molten metal suction part (5); the molten metal storage space (4) and the molten metal discharge part; A pump for molten metal, wherein the sliding valve (3) is provided with an in-valve communication path (7) so as to be switchable to a second state communicating with (6). 2. The molten metal accommodating space (4) is formed on both sides in the sliding direction of the piston (2), and the communication passage (7) in the valve is formed with respect to one of the molten metal accommodating spaces (4a). The first and second states can be switched between the first state and the second state, and the other molten metal storage space (4b) can be switched between the first and second states. 2. The pump for molten metal according to 1. 3. The first state and the second state, wherein the communication passage (7) in the valve is connected to the one molten metal storage space (4a).
A first communication path (7a) that can be switched to a state and a second communication path (7b) that can be switched to the first state and the second state with respect to the other molten metal storage space (4b). )
3. The pump according to claim 2, wherein the pump is formed separately. 4. The valve communication path (7) can be switched between the first state for the one molten metal storage space (4a) and the first state for the other molten metal storage space (4b). A liquid communication path (7c) and a discharge communication path (7d) that can be switched between the second state for the one molten metal storage space (4a) and the second state for the other molten metal storage space (4b). 3. The method according to claim 2, wherein
The pump for molten metal described in the above. 5. A structure in which a lower portion of the cylinder (1) is immersed in a molten metal, and a through hole (1b) communicating with the outside is provided below an immersion liquid surface of the cylinder (1). The pump for molten metal according to any one of claims 1 to 4, wherein (1b) is disposed above the molten metal suction part (5) and the molten metal discharge part (6). 6. An upper casing (8) for hermetically surrounding an upper part of the cylinder (1) and the piston shaft (2b) extending above the cylinder (1), wherein the upper casing (8) is provided. The molten metal pump according to any one of claims 1 to 5, wherein the inert gas is filled with the inert gas.