Ultra-large casting low-pressure casting equipment with multiple riser tubes and riser tube protection method

Abstract

The oversized casting low-pressure casting equipment comprises a heat preservation furnace, the multiple liquid rising pipes, an air inlet pipe and a plurality of bypass pipes, and a containing cavity used for containing molten liquid is formed in the heat preservation furnace; one end of each liquid rising pipe is communicated to the accommodating cavity, and the other end of each liquid rising pipe is selectively and externally connected to a mold cavity according to different to-be-cast castings; one end of the air inlet pipe is used for being externally connected with an air source, and the other end of the air inlet pipe is communicated into the containing cavity. The by-pass pipes and the liquid rising pipes are the same in number and are in one-to-one correspondence, and the by-pass pipes are communicated with the air inlet pipe and the corresponding liquid rising pipes. During use, the valve between the unused riser tube and the air inlet tube can be opened, and at the moment, the two ends of the unused riser tube are simultaneously communicated with the air inlet tube, the air pressures at the two ends are almost the same, and molten liquid cannot be pushed to flow through pressure difference, so that the riser tube does not need to be drawn out or blocked, molten aluminum cannot move upwards, and the unused riser tube does not need to be cleaned; and the flexibility is high.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of casting equipment, and particularly relates to a super-large casting low-pressure casting equipment with multiple riser tubes and a riser tube protection method. BACKGROUND

[0002] In the modern casting mode, low-pressure casting is widely applied due to its high material utilization rate, high-quality castings, high production efficiency and low cost, and good labor conditions. In low-pressure casting, the riser tube is an auxiliary material that plays a decisive role in product quality and production efficiency, but the value shared by the riser tube in use is ultimately determined by its service life. Even if any paint is brushed on the surface of the riser tube for protection, the service life is short, and the molten metal is contaminated. The later-used silicon carbide and aluminum oxide riser tubes cannot be corroded and cannot cause iron increase, but the heat preservation layer on the inner wall of the riser tube will gradually peel off when the aluminum slag and aluminum skin on the surface are cleaned, losing the heat preservation effect and even cracking and being scrapped. In addition, the above materials cannot adapt to the dramatic change in temperature, and when the temperature difference changes sharply, the riser tube is easily cracked and scrapped. Especially in the current situation of diversification and weight of products, the combination of multi-cavity and multi-mold in one machine is more and more common, and the proportion of multiple riser tubes is also increasing. However, all molds cannot meet only one production state, and the number of riser tubes used will change with the change of the mold, at which time how to deal with the unused riser tubes becomes a problem to be solved.

[0003] When there are multiple riser tubes on the casting machine, multiple sets of molds can be installed at the same time, or all the riser tubes are used to produce products large enough. However, not every time the same position or the same number of riser tubes are used, therefore, the number and position of the riser tubes needed by the mold at the moment need to be adapted, and the other unnecessary riser tubes are either lifted out to seal the channel opening or not lifted out to seal the pipe opening with a sealing pad to make the molten metal unable to flow out. The riser tubes lifted out in the former way are mostly scrapped due to the temperature difference caused by secondary installation, and the operation cannot be too fast, which will waste a lot of time. The latter way can prolong the service life of the riser tube by 3-5 times, but after the mold is disassembled every time, no matter what sealing pad is used, the pipe opening cannot be completely sealed, and a thick metal skin will be formed at the pipe opening, which needs to consume a lot of time to remove the metal skin, and a lot of manpower and material resources are wasted.

[0004] The information disclosed in this BACKGROUND section is only for the purpose of increasing the understanding of the background of the present application and should not be regarded as an acknowledgment or any form of suggestion that this information forms prior art that is publicly known. SUMMARY

[0005] The object of the present invention is to provide a low-pressure casting device for ultra-large castings with multiple riser pipes to solve the problem of handling unused riser pipes.

[0006] In order to achieve the above-mentioned purpose, a specific embodiment of the present invention provides a low-pressure casting equipment for ultra-large castings with multiple riser pipes, including a heat preservation furnace, multiple riser pipes, an air inlet pipe and multiple bypass pipes, wherein the heat preservation furnace is formed with a receiving cavity for placing the molten liquid; one end of each of the riser pipes is connected to the receiving cavity, and the other end of each riser pipe is used to selectively connect to the mold cavity according to different castings to be cast; one end of the air inlet pipe is used to connect to an external air source, and the other end is connected to the receiving cavity; the bypass pipe is connected to the riser pipe. The number of tubes is the same and corresponds one to one, and they are connected to the air inlet pipe and the corresponding riser pipe respectively; a valve is provided between the air inlet pipe and each riser pipe, and when the ultra-large casting low-pressure casting equipment with multiple riser pipes is in a working state, the multiple riser pipes are divided into a first riser pipe connected to the mold cavity and a second riser pipe not connected to the mold cavity, the valve between the first riser pipe and the air inlet pipe is in a closed state, and the valve between the second riser pipe and the air inlet pipe is in an open state.

[0007] In one or more embodiments of the present invention, the bypass pipe is detachably connected to the riser pipe.

[0008] In one or more embodiments of the present invention, the bypass pipe is detachably connected to the intake pipe.

[0009] In one or more embodiments of the present invention, the valve is disposed close to the air intake pipe.

[0010] In one or more embodiments of the present invention, the valve is close to the connection between the riser tube and the cavity.

[0011] In one or more embodiments of the present invention, the bypass pipe is a high-temperature resistant hose.

[0012] In one or more embodiments of the present invention, the bypass pipe is connected to the air inlet pipe and the riser pipe via a quick-change joint.

[0013] In one or more embodiments of the present invention, the furnace further includes a liquid inlet pipe disposed on an outer wall of the holding furnace and connected to the accommodating chamber, wherein the liquid inlet pipe is used to transport the melt into the accommodating chamber.

[0014] The present invention also provides a method for protecting a riser pipe of the ultra-large casting low-pressure casting equipment having multiple riser pipes, comprising the following steps:

[0015] S1. Fixing the mold to a low-pressure casting device for ultra-large castings having multiple riser pipes, and connecting one or more of the riser pipes to the mold cavity;

[0016] S2. Close the valve between the first liquid rising pipe and the air inlet pipe, and open the valve between the second liquid rising pipe and the air inlet pipe;

[0017] S3. The melt is transported into the holding furnace through the liquid inlet pipe, and gas is transported into the holding furnace through the air inlet pipe to press the melt into the mold cavity, and the melt is waited for solidification.

[0018] Compared to the prior art, the present invention's low-pressure casting equipment for ultra-large castings with multiple riser tubes connects each riser tube to the air inlet pipe and controls its on / off function through valves. The valves corresponding to the riser tubes in use are closed, allowing the molten metal in the holding furnace to be pressed into the mold cavity by the pressure differential. The valves corresponding to the unused riser tubes are opened. Since both ends of the riser tubes are connected to the air inlet pipe, the air pressure at both ends is the same, preventing the pressure differential from driving the molten metal. Therefore, there is no need to remove or seal the riser tubes, resulting in greater flexibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 A cross-sectional view of a low-pressure casting apparatus for ultra-large castings with multiple liquid lift pipes according to an embodiment of the present invention;

[0021] Figure 2 Flowchart of a method for protecting a riser pipe in one embodiment of the present invention.

[0022] Description of main reference numerals:

[0023] 100-Low-pressure casting equipment for ultra-large castings with multi-liter liquid pipes, 10-Holding furnace, 20-Liter liquid pipe, 30-Inlet pipe, 40-Bypass pipe, 50-Valve, 60-Mold, 70-Cavity, 80-Liquid aluminum. DETAILED DESCRIPTION

[0024] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0025] like Figure 1 As shown, an ultra-large casting low-pressure casting apparatus 100 with multiple riser pipes, according to one embodiment of the present invention, is primarily used for casting ultra-large castings (it can also be used for castings of other sizes). It includes a holding furnace 10, multiple riser pipes 20, an air inlet pipe 30, multiple bypass pipes 40, and a valve 50. The holding furnace 10 is provided with a chamber for storing molten aluminum 80 (which can also be other casting molten liquids; for ease of illustration, molten aluminum is used here as an example). The holding furnace 10 is equipped with multiple riser pipes 20, one end of which connects to the chamber of the holding furnace 10 and the other end of which selectively connects to the mold cavity 70 of the mold 60 to be produced, depending on the casting and its quantity. The air inlet pipe 30 has one end for connecting to an external gas source and the other end connected to the internal chamber. The air inlet pipe 30 pressurizes the chamber by delivering gas into the chamber, forcing the molten aluminum into the mold cavity 70 through the riser pipes 20. The bypass pipes 40 are the same in number as the riser pipes 20 and correspond one to one. The riser pipes 20 are connected to the intake pipe 30 through the bypass pipes 40. A valve 50 is provided between the intake pipe 30 and each riser pipe 20 to control the opening and closing of the bypass pipes 40.

[0026] Depending on the casting of different castings, multiple riser pipes 20 need to be selectively connected to the mold cavity 70 in the mold 60 corresponding to the different castings. When the ultra-large casting low-pressure casting equipment 100 with multiple riser pipes in this embodiment is in working state, the accommodating cavity is filled with molten aluminum 80. One end of the air inlet pipe 30 is connected to the external air source, and the other end is connected to the accommodating cavity and is located above the molten aluminum 80. In the working state, the riser pipe 20 can be divided into a first riser pipe 21 connected to the mold cavity 70 (due to the limitation of the viewing angle, the bypass pipe connected to the first riser pipe 21 is in the Figure 1 (not shown) and the second riser pipe 22, which is not connected to the mold cavity 70. Furthermore, when the ultra-large casting low-pressure casting equipment 100 with multiple riser pipes is in operation, the valve 50 between the second riser pipe 22 and the air inlet pipe 30 is open, while the valve 50 between the first riser pipe 21 and the air inlet pipe 30 is closed. When pressurized gas is supplied to the holding furnace 10 through the air inlet pipe 30, the valve 50 between the second riser pipe 22 and the air inlet pipe 30 is open, so the gas in the air inlet pipe 30 is split into two paths: one path directly flows into the accommodating chamber, and the other path passes through the bypass pipe 40 and the second riser pipe 22 and into the molten aluminum 80. As a result, the air pressure at the end (22A) of the second riser pipe 22 away from the accommodating chamber is almost the same as the air pressure within the accommodating chamber, preventing the molten aluminum 80 from flowing upward through the second riser pipe 22. However, since the valve 50 between the first riser pipe 21 and the air inlet pipe 30 is closed, the gas in the air inlet pipe 30 cannot flow to the end of the first riser pipe 21 close to the mold cavity 70. The air pressure at one end (21A) of the first riser pipe 21 at the mold cavity 70 is lower than the air pressure in the accommodating cavity. Under the action of the pressure difference, the aluminum liquid 80 flows upward through the first riser pipe 21 into the mold cavity 70.

[0027] Therefore, after setting the bypass pipe 40 and the valve 50, the valve 50 corresponding to the unused second rising pipe 22 can be opened to prevent the aluminum liquid from flowing up, thereby avoiding the blocking or disassembly of the rising pipe 20 that is not required to participate in the work, as well as the subsequent unnecessary operations such as removing the aluminum skin, and having high flexibility and production efficiency.

[0028] In the above embodiment, the number and positions of first riser tubes 21 are merely exemplary. Depending on the casting, multiple first riser tubes 21 may be selected, i.e., multiple riser tubes 20 may have one end connected to the cavity 70 within the mold 60 of the casting to be produced. In some cases, all riser tubes 20 may be connected to the cavity 70. In this case, the number of second riser tubes 22 is zero.

[0029] In one embodiment, the bypass pipe 40 is detachably designed. For example, the bypass pipe 40 is detachably connected to one of the riser pipe 20 and the air inlet pipe 30 , or is detachably connected to both of them, thereby improving flexibility.

[0030] Since each riser pipe 20 is provided with a bypass line, one or more riser pipes 20 can be selected for each production. In addition, the second riser pipe 22 that was not used can be activated for casting production in the middle of the production process, which is highly flexible.

[0031] In other embodiments, the riser pipe 20 used for a long time may also be selected not to be connected to the bypass pipe 40 (for example, Figure 1 The first riser pipe 21 in the embodiment is connected to the intake pipe 30 (e.g., the first riser pipe 21 in the embodiment) and only the riser pipe 20 that is not used is connected to the intake pipe 30 (e.g., the first riser pipe 21 in the embodiment) through the bypass pipe 40. Figure 1 The second riser pipe 22 in the embodiment of the present invention is provided, thereby further reducing production costs.

[0032] Specifically, although the bypass pipe 40 does not participate in the flow of molten aluminum, the temperature of the molten aluminum is relatively high, resulting in a relatively high temperature inside the bypass pipe 40. Therefore, in one embodiment, a high-temperature resistant hose is used as the bypass pipe 40. While ensuring the bypass effect, the flexible hose is also easy to connect and has high flexibility.

[0033] In one embodiment, the valve 50 can be located near the air inlet pipe 30. When there are a large number of riser pipes 20, centrally located valves 50 can also facilitate operation. Of course, for easier identification, the valve 50 can also be located near the riser pipe 20 near the mold cavity 70, and this embodiment is not limiting.

[0034] Preferably, the bypass pipe 40 is connected to the air inlet pipe 30 and the liquid riser 20 via a quick-change joint (such as a threaded joint, a bayonet joint, etc.), thereby achieving rapid disconnection and improving production efficiency.

[0035] like Figure 2 As shown, in combination with specific usage scenarios, a method for protecting the riser pipe 20 in the ultra-large casting low-pressure casting equipment 100 with multiple riser pipes in this embodiment is provided. After the bypass pipe 40 and the valve 50 are provided, the specific usage method includes the following steps:

[0036] S1 . Fix the mold 60 to the ultra-large casting low-pressure casting equipment 100 with multiple riser pipes, and connect the riser pipes 20 to the mold cavity 70 .

[0037] Specifically, the mold 60 is fixed to a low-pressure casting device 100 for ultra-large castings having multiple liter liquid pipes, and one of the liter liquid pipes 20 is connected to the mold cavity 70 .

[0038] S2. Close the valve 50 between the liquid riser 20 connected to the mold and the air inlet pipe 30, and open the valve 50 between the liquid riser 20 not connected to the mold and the air inlet pipe 30;

[0039] Specifically, the valve 50 between the riser pipe 20 connecting to the mold cavity and the air inlet pipe 30 is closed to prevent the air inlet pipe 30 from applying pressure at the connection point between the riser pipe 20 and the mold cavity. Simultaneously, the valve 50 between the unused riser pipe 20 and the air inlet pipe 30 is opened to connect both ends of the riser pipe 20 to the air inlet pipe 30. At this point, the pressure at both ends of the riser pipe 20 is equalized.

[0040] S3. Liquid aluminum is transported into the holding furnace through the liquid inlet pipe, and gas is transported into the holding furnace through the gas inlet pipe to press the aluminum liquid into the mold cavity.

[0041] After the connections are complete and the corresponding valves 50 are opened and closed, molten aluminum is delivered to the holding furnace 10 through the liquid inlet pipe, and then gas is delivered to the holding furnace 10 through the gas inlet pipe 30. Because the valve 50 corresponding to the liquid riser 20 connected to the mold cavity is closed, the pressure at one end of the mold cavity is lower than the pressure inside the furnace, forcing the molten aluminum into the cavity. However, since the pressure at both ends of the liquid riser 20 is not equalized, the molten aluminum cannot flow upward and is retained at one end of the furnace. After the molten aluminum in the mold cavity cools and solidifies, the mold is opened and the part is removed.

[0042] For example, in Figure 1 In the embodiment shown, after the mold 60 is fixedly connected to the ultra-large casting low-pressure casting equipment 100 with multiple liquid riser pipes, the first liquid riser pipe 21 is connected to the mold cavity 70 and the valve 50 in its corresponding pipeline is closed, and the valves 50 in the corresponding pipelines of the second liquid riser pipes 22 on both sides are opened, and then the air intake and pressurization operation is performed through the air intake pipe 30 to hydraulically pressurize the aluminum into the cavity 70 and wait for solidification.

[0043] In other embodiments, when the mold 60 bottom plate makes it impossible to directly connect the first liquid lifting pipe 21 to the cavity 70, a hole is drilled on the mold 60 bottom plate at a position corresponding to the second liquid lifting pipe 22, a joint is welded on the other end of the hole and connected to the bypass pipe 40, and the second liquid lifting pipe 22 is connected to the hole. At this time, one end of the second liquid lifting pipe 22 is connected to the air inlet pipe 30 through the bypass pipe 40, so that the second liquid lifting pipe 22 has the same pressure as the holding furnace 10, and the aluminum liquid cannot flow in the second liquid lifting pipe 22. However, attention should be paid during implementation. This method needs to drill a hole in the mold bottom plate, which may damage the consistency of the mold, and the sealing between the second liquid lifting pipe 22 and the hole needs to be ensured to avoid the situation that the aluminum liquid still flows in the second liquid lifting pipe 22 due to the gap.

[0044] By setting the bypass pipe 40 and the valve 50, the valve 50 corresponding to the unused second liquid lifting pipe 22 can be opened. At this time, the air pressure in the second liquid lifting pipe 22 is the same as the air pressure in the holding furnace 10, so the aluminum liquid cannot flow upward, avoiding the need to block or disassemble the liquid lifting pipe 20 that does not need to work. And because the aluminum liquid cannot flow upward, there will be no aluminum skin in the second liquid lifting pipe 22 after use, thus avoiding the need for subsequent operations such as removing the aluminum skin, protecting the second liquid lifting pipe 22, and improving flexibility and production efficiency.

[0045] It is apparent for those skilled in the art that the present application is not limited to the details of the above-described exemplary embodiments, but can be implemented in other concrete forms without departing from the spirit or essential characteristics of the present application. Therefore, the embodiments should be considered in all aspects as illustrative and not restrictive, and the scope of the present application is defined by the appended claims rather than the above description, and it is intended to encompass all changes falling within the meaning and range of equivalents of the elements of the claims. Any reference signs in the claims should not be considered as limiting the claims involved.

[0046] In addition, it should be understood that although the present specification is described in terms of embodiments, not every embodiment contains only one independent technical solution, and the description of the specification is only for the sake of clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can be appropriately combined to form other embodiments that those skilled in the art can understand.

Claims

1. A low-pressure casting equipment for ultra-large castings with a multi-liter liquid pipe, characterized in that: include: The holding furnace is formed with a receiving cavity for placing the melt; a plurality of riser pipes, one end of each of the riser pipes being connected to the accommodating cavity, and the other end of each of the riser pipes being used to selectively connect to the mold cavity according to different castings to be cast; an air inlet pipe, one end of which is used to connect to an external air source and the other end of which is connected to the accommodating cavity; and a plurality of bypass pipes, the number of which is the same as that of the riser pipes and which correspond one to one, and which are connected to the air inlet pipe and the corresponding riser pipe; A valve is provided between the air inlet pipe and each riser pipe, and when the ultra-large casting low-pressure casting equipment with multiple riser pipes is in a working state, the multiple riser pipes are divided into a first riser pipe connected to the mold cavity and a second riser pipe not connected to the mold cavity, the valve between the first riser pipe and the air inlet pipe is in a closed state, and the valve between the second riser pipe and the air inlet pipe is in an open state.

2. The ultra-large casting low-pressure casting equipment with multiple liquid pipes according to claim 1, characterized in that: The bypass pipe is detachably connected to the rising pipe.

3. The ultra-large casting low-pressure casting equipment with multiple liquid pipes according to claim 1, characterized in that: The bypass pipe is detachably connected to the air intake pipe.

4. The ultra-large casting low-pressure casting equipment with multiple liquid pipes according to claim 1, characterized in that: The valve is arranged close to the air inlet pipe.

5. The ultra-large casting low-pressure casting equipment with multiple liquid pipes according to claim 1, characterized in that: The valve is close to the connection between the riser tube and the cavity.

6. The ultra-large casting low-pressure casting equipment with multiple liquid pipes according to claim 1, characterized in that: The bypass pipe is a high temperature resistant hose.

7. The ultra-large casting low-pressure casting equipment with multiple liquid pipes according to claim 1, characterized in that: The bypass pipe is connected to the air inlet pipe and the liquid riser through a quick-change joint.

8. The ultra-large casting low-pressure casting equipment with multiple liquid-lift pipes according to claim 1, characterized in that: It also includes a liquid inlet pipe arranged on the outer wall of the insulation furnace and connected to the accommodating cavity, and the liquid inlet pipe is used to transport the melt into the accommodating cavity.

9. The method for protecting a riser pipe in a low-pressure casting device for ultra-large castings having multiple riser pipes according to claim 1, characterized in that: The following steps are involved: S1. Fixing the mold to a low-pressure casting device for ultra-large castings having multiple riser pipes, and connecting one or more of the riser pipes to the mold cavity; S2. Close the valve between the first liquid rising pipe and the air inlet pipe, and open the valve between the second liquid rising pipe and the air inlet pipe; S3. The melt is transported into the holding furnace through the liquid inlet pipe, and gas is transported into the holding furnace through the air inlet pipe to press the melt into the mold cavity, and the melt is waited for solidification.

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