JP2001289200A - Pump for molten metal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pump for molten metal capable of preventing molten metal from accidentally spouting together with pressurized air. SOLUTION: Each time a molten metal level in a pressure vessel 2 pressed down by feeding pressurized air is lowered sequentially less than a plurality of small diameter holes 15, the leaked amount of pressurized air increases steppingly to lower the pressure pressing down the molten metal. Then, the feeding amount of the molten metal is reduced steppingly. Eventually, the pressurized air leaks from four small diameter holes 15, and the feeding of the molten metal is stopped before the molten metal level reaches the lower end opening in the molten metal feed pipe 13. Accordingly, the pressurized air is prevented from being spouted together with the molten metal accidentally from the molten metal feed pipe 13. Depending on the size and drilled position, the number of the small diameter holes 15 can be limited to only one. In addition, instead of the small diameter holes 15, one groove, a plurality of parallel grooves with varying depth, or wedge-shaped grooves may be provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a pump for molten metal.

[0002]

2. Description of the Related Art After immersing in molten metal and flowing the molten metal through an inflow hole provided in the bottom surface, pressurized air is fed to a pressurized container having the inflow hole closed, and the upper end is pressurized. There is a molten metal pump configured to pump molten metal from a molten metal delivery pipe protruding outside the container.

[0003]

However, the above-mentioned pump for molten metal requires the pressurization of molten metal together with the molten metal when the pressurized air is continuously supplied even after the molten metal is delivered from the pressurized container into the molten metal delivery pipe. There is a possibility that the air may be gushes out. Although the pressure of the pressurized air may be controlled in accordance with the amount of the molten metal remaining in the pressurized container, the molten metal in the pressurized container cannot be visually observed. SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to provide a pump for molten metal in which molten metal is not unexpectedly ejected together with pressurized air.

[0004]

According to a first aspect of the present invention, there is provided a molten metal pump according to the present invention, wherein the molten metal flows through an inflow hole formed in a bottom surface of the molten metal. After that, a pressurized container to close the inflow hole,
A melting pump comprising: a pressure pump for pumping pressurized air to the pressure vessel; and a molten metal delivery pipe having a lower end opening approaching the bottom surface of the pressure vessel and an upper end protruding outside the pressure vessel. In the metal pump, a communication portion is provided at a lower end portion of the molten metal delivery pipe for increasing an amount of pressurized air leaking through the molten metal delivery pipe as the molten metal level decreases.

According to a second aspect of the present invention, there is provided a molten metal pump according to the first aspect, wherein the communicating portion has a small diameter hole.

According to a third aspect of the present invention, there is provided a molten metal pump according to the second aspect, wherein the small diameter hole is
A plurality of the molten metal delivery pipes are drilled at different distances from the lower end.

According to a fourth aspect of the present invention, there is provided a molten metal pump according to the first aspect of the present invention, wherein:
A groove cut from the lower end of the molten metal delivery pipe is provided.

According to a fifth aspect of the present invention, there is provided a molten metal pump according to the present invention, wherein a plurality of the grooves are formed in parallel with each other and the depth of each groove is changed. I do.

According to a sixth aspect of the present invention, there is provided a molten metal pump according to the fourth aspect, wherein the groove has a wedge shape.

[0010]

According to the pump for molten metal according to the first aspect of the present invention, the molten metal that has flowed into the pressurized container is pressurized and delivered to the molten metal delivery pipe, and the molten metal delivery pipe is provided. When the surface of the molten metal is lowered to the position of the communicating portion provided at the lower end of the tube, the communicating portion gradually appears, and pressurized air leaks into the molten metal delivery pipe. As the level of the molten metal drops, the amount of pressurized air leaking from the communicating portion to the molten metal delivery pipe increases. Initially, the amount of pressurized air leakage is small, so that the molten metal is bubbled out of the pump without pushing up the molten metal in the molten metal delivery pipe. And since the pressure which presses down a molten metal by pressure leak falls, the delivery of a molten metal stops before a molten metal surface reaches the lower end opening of a molten metal delivery pipe. Therefore, there is no fear that the pressurized air suddenly and vigorously blows out of the molten metal delivery pipe together with the molten metal.

According to the pump for molten metal according to the second aspect of the present invention, since the communicating portion has a small diameter hole, it is easy to work and can be formed at a predetermined drilled portion.

According to the third aspect of the present invention, since a plurality of small diameter holes are formed at different distances from the lower end of the molten metal delivery pipe, compressed air is introduced into the pressurized container. , The number of small-diameter holes that appear increases as the level of the molten metal lowers, and the amount of pressurized air leakage increases stepwise. As a result, the amount of the molten metal delivered decreases stepwise, and the delivery of the molten metal is stopped before the molten metal surface reaches the lower end opening of the molten metal delivery pipe.

According to the pump for molten metal according to the fourth aspect, the communicating portion is formed as a groove cut from the lower end of the molten metal delivery pipe. Leakage can be increased. Thereby, the delivery amount of the molten metal continuously decreases, and the delivery of the molten metal is stopped before the molten metal surface reaches the lower end opening of the molten metal delivery pipe. Further, since the groove can be formed only by cutting from the lower end of the molten metal delivery pipe, processing becomes easy.

According to the molten metal pump of the present invention, since a plurality of grooves serving as communicating portions are formed in parallel and the depths of the respective grooves are changed, the molten metal surface is lowered. The amount of pressurized air leakage that increases in proportion to the pressure can be increased stepwise.

According to the molten metal pump of the present invention, since the shape of the groove serving as the communication portion is wedge-shaped,
By the angle of the wedge-shaped groove, it is possible to change the degree of increase in the amount of pressurized air leakage that continuously increases as the molten metal surface level decreases.

[0016]

Embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a sectional view of a molten metal pump 1 according to the present invention. The bottomed cylindrical pressure vessel 2 is sealed by a lid 3 fastened to the upper end opening. A tubular casing 4 communicating with the pressurized container 2 is attached to the upper surface of the lid 3. An air cylinder 5 is attached to an upper end of the casing 4. In the casing 4, a lifting rod 7 directly connected to a piston 6 of an air cylinder 5 is hung down, and a mechanical seal 8 of a heat-resistant specification is provided to keep the airtight. In the middle of the casing 4, a fibrous heat insulating material 9 is filled. Furthermore, a pair of piping connection beaks 10a and 10b are attached to the casing 4.

A rod-shaped plug 12 for opening and closing a molten metal inflow hole 11 formed in the bottom surface of the pressure vessel 2 is connected to the lower end of the lifting rod 7 suspended in the pressure vessel 2. Further, a molten metal delivery pipe 13 inserted airtightly is fixed to the lid 3. The molten metal delivery pipe 13 has a lower end opening 14 approaching the bottom surface of the pressurized container 2. A small-diameter hole 15 as a communicating portion that causes air leakage of pressurized air through the molten metal delivery pipe 13 with a decrease in the molten metal surface on the lower end side surface of the molten metal delivery pipe 13, A plurality of holes are provided at different distances from the lower end. A curved pipe 16 having an end opening facing in the horizontal direction is connected to the upper end of the molten metal delivery pipe 13 protruding from the lid 3. Curved tube 1
A heater 17 is provided on the outer peripheral surface of the heater 6.

Specific dimensions of the molten metal pump 1 having the above-described configuration will be exemplified. The pressurized container 2 is a bottomed cylinder having a diameter of 250 mm and a length of 1,000 mm, and has a diameter of 20 m on the bottom surface.
m inflow holes 11 are formed. The molten metal delivery pipe 13 has a diameter of 50 mm, and is formed with four small-diameter holes having a diameter of about 3.5 mm, a distance from the lower end, and an interval between the small-diameter holes 15 of about 10 mm. Further, the pressurized container 2, the plug 12, the molten metal delivery pipe 13, the curved pipe 16, and the like immersed in the molten metal are preferably made of titanium or ceramics in order to prevent erosion and increase durability.

The molten metal pump 1 is used for pumping a molten metal of aluminum.
The flange 3a of the lid 3 is hung over the opening 23 of the upper lid 22, and the pressurized container 2 is immersed in the molten aluminum. After the aluminum melt flows into the pressurized container 2 from the inflow hole 11 on the bottom surface, the air cylinder 5 is operated to lower the lifting rod 7, and the inflow hole 11 is closed by the plug 12. At the same time, the pipe connecting beak 10 attached to the casing 4
A pressurized air fed by a pressurizing pump 25 is fed into the pressurized container 2 from a pipe 24 connected to a.

The aluminum melt, which is depressed by the pressure of the pressurized air, is delivered from the molten metal delivery pipe 13 and pumped out through the curved pipe 16. The cooling of the molten aluminum is prevented by the heater 17 disposed on the outer peripheral surface of the curved tube 16. The surface of the molten metal that has flowed into the pressurized container 2 has a small diameter hole 1 formed at the top of the molten metal delivery pipe 13.
When the pressure drops to 5, the pressurized air leaks from the small-diameter hole 15 to the molten metal delivery pipe 13. Small-diameter hole 15 with a diameter of about 3.5 mm
Therefore, the amount of pressurized air leaking into the molten metal delivery pipe 13 is small, so that the molten metal is bubbled out of the pump without pushing up the molten metal in the delivery pipe 13. When the molten metal is further reduced to the next smaller diameter hole 15 by the supply of the compressed air, the compressed air leaks from the two small diameter holes 15 to the molten metal delivery pipe 13.

The pressurized air is continuously sent to the pressurized container 2, and the molten metal in the pressurized container 2 is reduced in pressure. Each time the gas leaks, the pressure for lowering the molten metal gradually decreases. Therefore, the delivery amount of the molten metal gradually decreases, and finally, the delivery of the molten metal is stopped before the molten metal surface reaches the lower end opening of the molten metal delivery pipe 13. When the delivery of molten metal is stopped,
0b is opened to release the pressurized container 2 to the atmosphere, and the air cylinder 5 is operated to raise the elevating rod 7.
When the lifting rod 7 is raised, the plug 12 is pulled up to open the inflow hole 11, and the molten metal in the molten metal container 21 is removed from the pressure vessel 2.
Flows into. Pressurized container 2 up to the surface of molten metal in molten metal container 21
After the molten metal has flowed into the inside, the inflow hole 11 is closed, and pressurized air is supplied to pump out the molten metal as described above.

As described above, each time the level of the molten metal in the pressure vessel 2 which is depressed by the supply of the pressurized air falls below the plurality of small-diameter holes 15, the leakage amount of the pressurized air increases stepwise. As a result, the pressure for lowering the molten metal decreases, and the amount of molten metal delivered decreases stepwise. Eventually, pressurized air leaks from the four small-diameter holes 15, and the delivery of the molten metal stops before the molten metal surface reaches the lower end opening of the molten metal delivery pipe 13.
Therefore, the pressurized air does not suddenly blow out from the molten metal delivery pipe 13 together with the molten metal. The number of the small diameter holes 15 may be only one depending on the size and the drilling position.

FIGS. 3 (a) to 3 (c) show a modified example of the communicating portion for increasing the air leakage of the pressurized air through the molten metal delivery pipe 13 as the molten metal surface level decreases. It is. The communication part shown in FIG. 3 (a) is formed by cutting the groove 31 from the lower end of the molten metal delivery pipe 13, and continuously increases the amount of pressurized air leakage in proportion to a decrease in the level of the molten metal. it can. Further, since the groove 31 can be formed only by cutting from the lower end of the molten metal delivery pipe 13, the processing is facilitated. FIG.
The communicating part shown in (b) has three parallel grooves 31a and 31.
b, 31c are formed by cutting from the lower end of the molten metal delivery pipe 13, and the depth of each groove is changed. Therefore, the degree of increase in the amount of pressurized air leakage that increases in proportion to the decrease in the molten metal surface can be increased stepwise.
The communication portion shown in FIG. 3C is provided with a wedge-shaped groove 32 at the lower end of the molten metal delivery pipe 13.
Can increase the degree of increase in the amount of leakage of pressurized air that continuously increases as the molten metal level decreases.

[Brief description of the drawings]

FIG. 1 is a sectional view of a molten metal pump.

FIG. 2 is a perspective view of a lower end portion of the molten metal delivery pipe.

FIG. 3 shows a modified example of the communication unit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Pump for molten metal 2 ... Pressurized container 11 ... Inflow hole 12 ... Plug 13 ... Molten metal delivery pipe 14 ... Lower end opening 15 ... Small diameter hole 25 ... .Pressure pump 31, 31a-31c ... groove 32 ... wedge-shaped groove

Continued on the front page (72) Inventor Mitsumasa Nakayama 638-2 Akechi-cho, Ena-gun, Gifu F-term (reference) 3H079 AA01 AA05 BB10 CC24 DD02 DD08 DD13 DD24 DD41 4E014 LA09 4K055 AA04 JA20

Claims (6)

[Claims] 1. A pressurized container that is immersed in a molten metal and flows in from an inflow hole provided in a bottom surface and then closed the inflow hole, and pressurized air is fed to the pressurized container. A pressure pump, and a molten metal pump having a lower end opening approaching the bottom surface of the pressure vessel and a molten metal delivery pipe having an upper end protruding outside the pressure vessel; A pump for molten metal, wherein a communication portion is provided at a lower end portion for increasing an amount of pressurized air leaking through the molten metal delivery pipe as the molten metal level decreases. 2. The molten metal pump according to claim 1, wherein the communication portion has a small diameter hole. 3. The molten metal pump according to claim 2, wherein a plurality of the small diameter holes are formed at different distances from a lower end of the molten metal delivery pipe. 4. The molten metal pump according to claim 1, wherein the communicating portion is a groove cut from a lower end of the molten metal delivery pipe. 5. A plurality of said grooves are formed in parallel,
The depth of each groove is changed.
2. The pump for molten metal according to claim 1. 6. The molten metal pump according to claim 4, wherein said groove has a wedge shape.