Self-sealing vacuum sub-continuous casting crucible system and working method thereof

Abstract

This invention belongs to the field of fluid hydraulic technology, specifically relating to a self-sealing vacuum bottom-casting crucible system and its working method. The self-sealing vacuum bottom-casting crucible system includes: a furnace shell containing a cavity, the side wall of which has an installation through-hole; a crucible disposed within the cavity, its side wall having a drain hole containing a plug; and a hydraulic cylinder with a piston rod adapted to extend into the installation through-hole, forming an annular gap between the piston rod and the through-hole. The self-sealing vacuum bottom-casting crucible system and its working method utilize a hydraulic cylinder to push the plug on the crucible to expel molten metal, avoiding electromagnetic interference. Simultaneously, the piston rod is installed in a non-contact manner to reduce heat transfer, thereby preventing hydraulic oil failure due to prolonged overheating. Furthermore, a sealing mechanism is used to cut off the annular gap when the piston rod pushes open the plug, preventing cold air from entering the cavity and accelerating the cooling of the molten metal inside the crucible.

Description

Technical Field

[0001] This invention belongs to the field of fluid hydraulic technology, specifically relating to a straight cylinder type fluid hydraulic system, and more particularly to a self-sealing vacuum bottom casting crucible system and its working method. Background Technology

[0002] Vacuum casting, as one of the three continuous casting technologies (upward, horizontal, and downward) for metal raw material production, has a wide range of applications, including the production of traditional steel, copper alloys, and even precious metals such as gold and silver jewelry raw materials.

[0003] In related technologies, when a vacuum continuous casting crucible malfunctions and the machine stops, the mold hole of the crucible will close, i.e., the casting process will stop. At this time, the molten metal inside the crucible cannot flow out and will cool and solidify inside the crucible, making it impossible to remove. If the crucible is subsequently melted again by reheating, it is easy for it to break.

[0004] Therefore, how to solve the technical problem that molten metal is prone to cracking when reheated after cooling and solidification in the crucible after equipment shutdown is a problem that urgently needs to be solved by those skilled in the art.

[0005] It should be noted that the information disclosed in this background section is only for understanding the background technology of the present application concept, and therefore, the above description is not considered to constitute prior art information. Summary of the Invention

[0006] This disclosure provides at least one self-sealing vacuum bottom casting crucible system and its operating method.

[0007] In a first aspect, embodiments of this disclosure provide a self-sealing vacuum casting crucible system, comprising: a furnace shell containing a cavity connected to a negative pressure generator, the cavity having a mounting through hole on its side wall; a crucible disposed within the cavity, the crucible having a drain hole on its side wall, a plug being disposed within the drain hole; a hydraulic cylinder having a piston rod adapted to extend into the mounting through hole, forming an annular gap between the piston rod and the mounting through hole; wherein a sealant is disposed within the annular gap, and a sealing mechanism is disposed on the side wall of the piston rod; when the cavity is under vacuum, the sealing mechanism is adapted to retract into the piston rod; when the cavity is not under vacuum, the sealing mechanism is adapted to extend outward to cut off the annular gap, and subsequently the hydraulic cylinder is adapted to drive the piston rod outward to push open the plug.

[0008] In one alternative embodiment, the sealant is located at the outer end of the annular gap away from the crucible.

[0009] In one optional embodiment, the sealing mechanism includes: a pressure chamber disposed within the piston rod and communicating with a cavity; a movable piece located within the pressure chamber to separate the pressure chamber from the cavity; a plurality of sealing pieces arranged circumferentially along the piston rod; and a spring located within the pressure chamber and connected to the movable piece; wherein the pressure chamber is set with positive pressure, causing each sealing piece to extend out of the piston rod to cut off the annular gap; when the cavity is under vacuum, the movable piece is forced to move outward, causing the pressure chamber to form negative pressure, thereby driving each sealing piece to retract back to the piston rod; when the cavity stops under vacuum, the spring drives the movable piece to reset and move so that the pressure chamber returns to positive pressure.

[0010] In one alternative embodiment, adjacent sealing plates are staggered and their head and tail ends coincide, so that the annular gap is cut off when each sealing plate extends out of the piston rod.

[0011] In one optional embodiment, the blocking portion of the sealing plate is fan-shaped, and the sliding portion is rectangular.

[0012] In one alternative embodiment, the plug is in the shape of an inverted cone; a flow channel is provided in the cavity; the flow channel is located below the vent hole and is adapted to receive the melt discharged from the vent hole.

[0013] In one optional embodiment, a lower guide mold is provided on the lower surface of the crucible; the upper end of the lower guide mold is connected to the crucible, and the lower end extends out of the cavity.

[0014] Secondly, this disclosure also provides a method for operating a self-sealing vacuum continuous casting crucible system, comprising: extending the piston rod of a hydraulic cylinder into the mounting through hole of the furnace shell to form an annular gap; applying sealant to the annular gap to seal the mounting through hole; when the cavity is under vacuum, retracting the sealing mechanism on the piston rod into the piston rod; when the cavity stops under vacuum, extending the sealing mechanism on the piston rod to cut off the mounting through hole, and then controlling the hydraulic cylinder to extend the piston rod to push open the plug of the crucible.

[0015] In one alternative embodiment, the method of extending the sealing mechanism on the piston rod to cut off the mounting through hole when the vacuum in the cavity stops, and then controlling the hydraulic cylinder to extend the piston rod to push open the plug of the crucible includes: moving each moving piece outward by the positive pressure of the pressure chamber to cut off the mounting through hole; extending the piston rod outward by the hydraulic cylinder to push open the plug of the crucible; and breaking the sealant seal by extending the piston rod.

[0016] In one optional embodiment, the method of retracting the sealing mechanism on the piston rod into the piston rod when the cavity is under vacuum includes: moving the moving plate of the piston rod outward by the negative pressure of the cavity to create a negative pressure in the pressure chamber; and retracting each sealing plate back into the piston rod by the negative pressure in the pressure chamber.

[0017] The beneficial effects of this invention are that the self-sealing vacuum continuous casting crucible system and its working method use a hydraulic cylinder to push the plug on the crucible to vent the molten metal, thus avoiding electromagnetic interference; at the same time, the piston rod is installed in a non-contact manner to reduce the heat transfer, thereby preventing the hydraulic oil from failing due to overheating over a long period of time; and by setting a sealing mechanism, the annular gap is cut off when the piston rod pushes open the plug to prevent cold air from entering the cavity and thus accelerate the cooling of the molten metal in the crucible.

[0018] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention are realized and obtained through the structures particularly pointed out in the description and the drawings.

[0019] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0020] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the structure of a self-sealing vacuum bottom casting crucible system provided in an embodiment of the present disclosure;

[0022] Figure 2 This is a cross-sectional structural schematic diagram of a self-sealing vacuum bottom casting crucible system provided in an embodiment of the present disclosure;

[0023] Figure 3 This is a schematic diagram of the structure of a mounting through hole and a drain hole provided in an embodiment of the present disclosure;

[0024] Figure 4 This is a schematic diagram of the structure of an annular gap during normal operation, provided by an embodiment of the present disclosure;

[0025] Figure 5 This is a schematic diagram of the annular gap structure during shutdown provided by an embodiment of the present disclosure;

[0026] Figure 6 This is a schematic diagram of a piston rod pushing open a plug body according to an embodiment of the present disclosure;

[0027] Figure 7 This is a schematic diagram of the structure of a piston rod provided in an embodiment of the present disclosure;

[0028] Figure 8 A cross-sectional view of a piston rod provided in an embodiment of this disclosure;

[0029] Figure 9 This is a schematic diagram of the structure of a sealing patch provided in an embodiment of this disclosure.

[0030] In the picture:

[0031] Furnace body shell 1, cavity 11, mounting through hole 12, annular gap 13, sealant 14;

[0032] Crucible 2, plug 21, drain hole 22;

[0033] Hydraulic cylinder 3, piston rod 31, sealing mechanism 32, pressure chamber 321, moving plate 322, sealing plate 323, sealing part 323a, sliding part 323b, limiting block 323c, spring 324, mounting position 325;

[0034] Flow channel 4;

[0035] Lower mold 5. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the figures, the thickness of parts may be exaggerated or reduced for the purpose of effectively depicting the technical content.

[0038] The following detailed description of some embodiments of the present invention is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0039] like Figure 1 , Figure 2As shown, at least one embodiment provides a self-sealing vacuum casting crucible system, including: a furnace shell 1, a crucible 2, and a hydraulic cylinder 3; wherein, a cover is provided on the furnace shell 1, and the cover is connected to a negative pressure generator through a pipe to create a vacuum in the cavity 11 inside the furnace shell 1 and the cover when the negative pressure generator is working; the crucible 2 is disposed inside the cavity 11; and the hydraulic cylinder 3 is disposed on the side wall of the furnace shell 1; wherein, the cover and the negative pressure generator are not shown in the figure.

[0040] Since the molten metal in the downward continuous casting flows at a high level, when the equipment fails and stops, the molten metal in crucible 2 needs to be emptied to prevent the molten metal from cooling and solidifying inside crucible 2.

[0041] To solve the above problems, such as Figure 2 , Figure 3 As shown, in some embodiments, the side wall of the crucible 2 is provided with a drain hole 22, and a plug 21 is provided in the drain hole 22 to block the drain hole 22.

[0042] In this embodiment, the plug 21 can be a graphite plug. During normal operation, the plug 21 blocks the drain hole 22. When it is necessary to discharge molten metal, the plug 21 is pushed open by the hydraulic cylinder 3. However, the hydraulic cylinder 3 cannot be replaced by solenoid valves, motors, or other drive components involving electronic control, because these components will cause electromagnetic interference with the induction coil of the medium frequency induction furnace.

[0043] like Figure 2 , Figure 3 As shown, in some embodiments, the side wall of the cavity 11 is provided with a mounting through hole 12, and the piston rod 31 of the hydraulic cylinder 3 extends into the mounting through hole 12.

[0044] In this embodiment, the piston rod 31 does not contact the plug body 21 to prevent the high temperature of the crucible 2 from being directly transmitted to the hydraulic cylinder 3 through the piston rod 31, which could lead to hydraulic oil failure or even damage to the hydraulic cylinder 3. When the equipment malfunctions and stops, the negative pressure generator stops working, causing the cavity 11 to not be vacuumed. At this time, the hydraulic cylinder 3 can control the piston rod 31 to extend outward to push the plug body 21 open.

[0045] like Figure 4 As shown, in some embodiments, an annular gap 13 is formed between the piston rod 31 of the hydraulic cylinder 3 and the mounting through hole 12.

[0046] In this embodiment, the presence of the annular gap 13 prevents the piston rod 31 from contacting the furnace shell 1, thus preventing the temperature of the furnace shell 1 from being directly transferred to the hydraulic cylinder 3 via the piston rod 31, thereby further reducing the heat on the hydraulic cylinder 3.

[0047] like Figure 4As shown, in some embodiments, a sealant 14 is provided in the annular gap 13, and the sealant 14 is located at the outer end of the annular gap 13 away from the crucible 2.

[0048] In this embodiment, since the piston rod 31 is installed in a non-contact manner, the cavity 11 will leak air due to the presence of the annular gap 13. Therefore, it is necessary to seal it with sealant 14. At the same time, the sealant 14 is applied as far away from the crucible 2 as possible to reduce the heat on the furnace shell 1 from being transferred to the piston rod 31 through the sealant 14.

[0049] In this embodiment, the reason why a sealing ring cannot be used to seal the annular gap 13 is that the hydraulic cylinder 3 is only used in case of an emergency shutdown, that is, the frequency of use is very low. Therefore, the sealing of the annular gap 13 can be directly prevented by using sealant 14 to seal it. If a sealing ring is used to seal it, the sealing of the sealing ring is likely to fail if it is not used or maintained for a long time.

[0050] like Figure 4 , Figure 5 As shown, in some embodiments, a sealing mechanism 32 is provided on the side wall of the piston rod 31; when the cavity 11 is under vacuum (e.g. Figure 4 As shown), the sealing mechanism 32 is adapted to retract into the piston rod 31; when the cavity 11 stops vacuuming (e.g. Figure 5 As shown), the sealing mechanism 32 is adapted to extend outward to cut off the annular gap 13, and then (as shown) Figure 6 As shown), the hydraulic cylinder 3 is adapted to drive the piston rod 31 to extend outward to push open the plug body 21.

[0051] In this embodiment, when the equipment malfunctions and stops, the negative pressure generator stops working, causing the cavity to lose its vacuum. At this time, the operator controls the hydraulic cylinder 3 (which is connected to the backup power supply) to extend the piston rod 31 to push open the plug body 21. The movement of the piston rod 31 will cause the sealant 14 to break, allowing cold air from the outside to enter the cavity 11 through the annular gap 13, thereby accelerating the cooling of the molten metal in the crucible 2. Therefore, this embodiment sets up a sealing mechanism 32 to extend and cut off the annular gap 13 when the cavity 11 stops vacuuming (i.e., when the equipment malfunctions and stops), thereby preventing cold air from entering the cavity 11 through the annular gap 13 after the piston rod 31 moves.

[0052] like Figure 7 , Figure 8As shown, in some embodiments, the sealing mechanism 32 includes: a pressure chamber 321, which is opened along the axis of the piston rod 31 and communicates with the cavity 11; a movable piece 322, which is located in the pressure chamber 321 to separate the pressure chamber 321 from the cavity 11; a plurality of sealing pieces 323, which are arranged circumferentially along the piston rod 31; and a spring 324, which is located in the pressure chamber 321 and connected to the movable piece 322.

[0053] In this embodiment, the initial state is as follows: the pressure chamber 321 is set with positive pressure, causing each sealing piece 323 to extend out of the piston rod 31 to cut off the annular gap 13; when the cavity 11 is under vacuum, the negative pressure of the cavity 11 will drive the moving piece 322 to move outward to increase the volume of the pressure chamber 321, until the negative pressure of the pressure chamber 321 causes each moving piece 322 to retract into the piston rod 31, avoiding contact between the moving piece 322 and the inner wall of the mounting through hole 12 for heat conduction; when the cavity 11 stops being under vacuum, the moving piece 322 resets and moves to restore the pressure chamber 321 to positive pressure, causing each sealing piece 323 to extend out of the piston rod 31 to cut off the annular gap 13.

[0054] like Figure 7 As shown, in some embodiments, adjacent sealing pieces 323 are staggered and their head and tail ends coincide, so that each sealing piece 323 cuts off the annular gap 13 when it extends out of the piston rod 31.

[0055] In this embodiment, this arrangement is to make the cross-section of each sealing piece 323 after it extends outwards circular, so as to cut off the annular gap 13.

[0056] like Figure 8 As shown, in some embodiments, the side wall of the piston rod 31 is provided with a plurality of mounting positions 325 for mounting the sealing plate 323, and the sealing plate 323 is slidably disposed in the mounting position 325.

[0057] like Figure 9 As shown, in some embodiments, the blocking portion 323a of the blocking piece 323 is fan-shaped, the sliding portion 323b is rectangular, and the sidewall of the blocking portion 323a is provided with a limiting block 323c.

[0058] In this embodiment, the sliding part 323b of the sealing piece 323 is slidably disposed in the mounting position 325; the cross-section of the sliding part 323b is rectangular in order to prevent the pressure chamber 321 from leaking air during the movement of the sealing piece 323; the function of the limiting block 323c is to limit the movement distance of the sealing piece 323.

[0059] like Figure 4 As shown, in some embodiments, the plug 21 is inverted conical in shape; a flow channel 4 is provided inside the cavity 11; the flow channel 4 is located below the drain hole 22 and is suitable for receiving the melt discharged from the drain hole 22.

[0060] In some embodiments, a lower guide mold 5 is provided on the lower surface of the crucible 2; the upper end of the lower guide mold 5 is connected to the crucible 2, and the lower end extends out of the cavity 11.

[0061] At least one embodiment also provides a method of operating a self-sealing vacuum casting crucible system, comprising: extending the piston rod 31 of the hydraulic cylinder 3 into the mounting through hole 12 of the furnace shell 1 to form an annular gap 13; applying sealant 14 into the annular gap 13 to seal the mounting through hole 12; when the cavity 11 is under vacuum, retracting the sealing mechanism 32 on the piston rod 31 into the piston rod 31; when the cavity 11 is not under vacuum, extending the sealing mechanism 32 on the piston rod 31 to cut off the mounting through hole 12, and then controlling the hydraulic cylinder 3 to extend the piston rod 31 to push open the plug 21 of the crucible 2.

[0062] In some embodiments, when the vacuum in the cavity 11 is stopped, the sealing mechanism 32 on the piston rod 31 extends outward to cut off the mounting through hole 12, and then the hydraulic cylinder 3 is controlled to extend the piston rod 31 outward to push open the plug 21 of the crucible 2. The method includes: driving each moving piece 322 outward to cut off the mounting through hole 12 by the positive pressure of the pressure chamber 321; driving the piston rod 31 outward to push open the plug 21 of the crucible 2 by the hydraulic cylinder 3; and causing the sealant 14 to break through the seal by the extension of the piston rod 31.

[0063] In some embodiments, when the cavity 11 is under vacuum, the method of retracting the sealing mechanism 32 on the piston rod 31 into the piston rod 31 includes: moving the movable piece 322 of the piston rod 31 outward by the negative pressure of the cavity 11 to make the pressure chamber 321 negative; and retracting each sealing piece 323 back into the piston rod 31 by the negative pressure of the pressure chamber 321.

[0064] For the specific structure and implementation process of the self-sealing vacuum continuous casting crucible system, please refer to the relevant discussion in the above embodiments, which will not be repeated here.

[0065] In summary, this self-sealing vacuum casting crucible system and its working method utilize a hydraulic cylinder 3 to push the plug 21 on the crucible 2 to expel the molten metal, thus avoiding electromagnetic interference. At the same time, the piston rod 31 is installed in a non-contact manner to reduce the heat transfer, thereby preventing the hydraulic oil from failing due to prolonged overheating. Furthermore, by setting a sealing mechanism 32, the annular gap 13 is cut off when the piston rod 31 pushes open the plug 21 to prevent cold air from entering the cavity 11 and accelerating the cooling of the molten metal in the crucible 2.

[0066] In this document, when it is said that the first component is located on the second component, this can mean that the first component can be directly formed on the second component, or that the third component can be inserted between the first component and the second component.

[0067] In this document, when an element or layer is referred to as “located,” “joined to,” “connected to,” “attached to,” or “coupled to” another element or layer, it may be directly located, joined, connected, attached to, or coupled to the other element or layer, or there may be intermediate elements or layers present. Conversely, when an element is referred to as “directly on another element or layer,” “directly joined to,” “directly connected to,” “directly attached to,” or “directly coupled to” another element or layer, there may be no intermediate elements or layers present. Other terms used to describe relationships between elements should be interpreted in a similar manner (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). As used herein, the term “and / or” includes any and all combinations of one or more of the related listed items.

[0068] In this document, exemplary embodiments of the present disclosure will be described in more detail with reference to the accompanying drawings. As used herein, expressions such as “at least one of…” modify the entire list of elements when following a list of elements, rather than individual elements in the list. For example, the expression “at least one of a, b, and c” should be understood to include only a, only b, only c, both a and b, both a and c, both b and c, or all of a, b, and c.

[0069] The terminology used herein is for the purpose of describing specific exemplary configurations only and is not intended to be limiting. As used herein, the singular articles “a,” “an,” and “the” may also be intended to include plural forms unless otherwise clearly stated herein. The terms “comprising,” “including,” and “having” are inclusive and thus specify the presence of features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof. The method steps, processes, and operations described herein should not be construed as requiring them to be performed in the specific order discussed or shown, unless specifically identified as such. Additional or alternative steps may be employed.

[0070] As used herein, the phrases “in one embodiment,” “according to one embodiment,” “in some embodiments,” etc., generally refer to the fact that a particular feature, structure, or characteristic following the phrase can be included in at least one embodiment of this disclosure. Therefore, a particular feature, structure, or characteristic can be included in more than one embodiment of this disclosure, such that these phrases do not necessarily refer to the same embodiment. As used herein, the terms “example,” “exemplary,” etc., are used to “serve as an example, instance, or illustration.” Any implementation, aspect, or design described herein as “example” or “exemplary” is not necessarily to be construed as preferred or superior to other implementations, aspects, or designs. Rather, the use of the terms “example,” “exemplary,” etc., is intended to present concepts in a specific manner.

[0071] In the description of the embodiments of the present invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention based on the specific circumstances.

[0072] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, terms such as "first," "second," and other numerical terms used herein do not imply order or sequence unless expressly indicated herein. Therefore, without departing from the teachings of the exemplary embodiments, the first element, component, region, layer, or segment discussed above may be referred to as a second element, component, region, layer, or segment.

[0073] Spatially relative terms, such as “inside,” “outside,” “below,” “below,” “down,” “above,” “up,” etc., may be used herein to describe the relationship between one element or feature illustrated in the figures and another element or feature. In addition to the orientations depicted in the figures, spatially relative terms may be intended to cover different orientations of the device in use or operation. For example, if the device in the figure is flipped, an element described as “below” or “below” other elements or features would be oriented as “above” other elements or features. Thus, the example term “below” can cover both above and below orientations. The device may be oriented in other ways (rotated 90 degrees or in other orientations), and the spatially relative descriptors used herein are interpreted accordingly.

[0074] In the above discussion, unless otherwise stated, when used to describe numerical values, the terms “about,” “approximately,” “basically,” etc., indicate a change of + / - 10% in that value.

[0075] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A self-sealing, under-vacuum, transfer-continuous-casting- crucible system, characterized in that, It includes: Furnace shell (1), which is a cavity (11) inside, the cavity (11) is connected with negative pressure generator, the side wall of the cavity (11) is provided with installation through hole (12); Crucible (2) is arranged in the cavity (11), and the side wall is provided with the flow hole (22), the flow hole (22) is provided with plug body (21); Hydraulic cylinder (3), the piston rod (31) thereof is adapted to extend into the installation through hole (12), and the annular gap (13) is formed between the installation through hole (12); wherein The annular gap (13) is provided with sealing glue (14), and the side wall of the piston rod (31) is provided with sealing mechanism (32); When the cavity (11) is vacuum, the sealing mechanism (32) is adapted to retract into the piston rod (31); When the cavity (11) stops vacuum, the sealing mechanism (32) is adapted to extend outward to cut off the annular gap (13), and then the hydraulic cylinder (3) is adapted to drive the piston rod (31) to extend outward to open the plug body (21).

2. The self-sealing vacuum drawing continuous casting crucible system according to claim 1, wherein The sealing glue (14) is located at the outer end of the annular gap (13) to be away from the crucible (2).

3. The self-sealing vacuum drawing continuous casting crucible system according to claim 1, wherein The sealing mechanism (32) comprises: Pressure chamber (321) is arranged in the piston rod (31), and is communicated with the cavity (11); The moving piece (322) is located in the pressure chamber (321) to separate the pressure chamber (321) from the cavity (11); A plurality of sealing pieces (323) are arranged along the circumference of the piston rod (31); Spring (324) is located in the pressure chamber (321), and is connected with the moving piece (322); Wherein, the pressure chamber (321) is positively pressure set, so that each sealing piece (323) extends out of the piston rod (31) to cut off the annular gap (13); When the cavity (11) is vacuum, the moving piece (322) is forced to move outward to form negative pressure in the pressure chamber (321) to drive each sealing piece (323) to retract into the piston rod (31); When the cavity (11) stops vacuum, the spring (324) drives the moving piece (322) to reset to make the pressure chamber (321) restore positive pressure.

4. The self-sealing vacuum drawing continuous casting crucible system according to claim 3, wherein The adjacent sealing pieces (323) are arranged in staggered mode and the leading end and the trailing end are coincident, so that each sealing piece (323) extends out of the piston rod (31) to cut off the annular gap (13).

5. The self-sealing vacuum drawing continuous casting crucible system according to claim 4, wherein The sealing part (323a) of the sealing piece (323) is fan-shaped, and the sliding part (323b) is rectangular.

6. The self-sealing vacuum drawing continuous casting crucible system according to claim 5, wherein The plug body (21) is inverted conical type; The cavity (11) is provided with a flow channel (4); The flow channel (4) is located below the flow hole (22) and is adapted to receive the melt discharged from the flow hole (22).

7. The self-sealing vacuum down-casting crucible system of claim 6, wherein, a lower surface of the crucible (2) is provided with a down-casting mold (5); an upper end of the down-casting mold (5) is communicated with the crucible (2), and a lower end of the down-casting mold (5) extends out of the cavity (11).

8. A method of operating a self-sealing, under-vacuum, continuous-casting- crucible system as claimed in any one of claims 3 to 7, characterized in that, comprising: extending a piston rod (31) of a hydraulic cylinder (3) into a mounting through hole (12) of a furnace body shell (1) and forming an annular gap (13); applying a sealant (14) in the annular gap (13) to seal the mounting through hole (12); when the cavity (11) is in vacuum, a blocking mechanism (32) on the piston rod (31) is retracted into the piston rod (31); when the cavity (11) stops being in vacuum, the blocking mechanism (32) on the piston rod (31) is extended to cut off the mounting through hole (12), and then the hydraulic cylinder (3) is controlled to extend the piston rod (31) to knock off a plug (21) of the crucible (2).

9. The working method of the self-sealing vacuum down-casting crucible system of claim 8, wherein, the method of, when the cavity (11) stops being in vacuum, extending the blocking mechanism (32) on the piston rod (31) to cut off the mounting through hole (12), and then controlling the hydraulic cylinder (3) to extend the piston rod (31) to knock off the plug (21) of the crucible (2) comprises: driving each moving piece (322) to move outward to cut off the mounting through hole (12) by positive pressure of a pressure chamber (321); extending the piston rod (31) to knock off the plug (21) of the crucible (2) by the hydraulic cylinder (3); breaking the seal of the sealant (14) by the extension of the piston rod (31).

10. The working method of the self-sealing vacuum down-casting crucible system of claim 9, wherein, the method of, when the cavity (11) is in vacuum, retracting the blocking mechanism (32) on the piston rod (31) into the piston rod (31) comprises: driving the moving piece (322) of the piston rod (31) to move outward to make the pressure chamber (321) negative pressure by negative pressure of the cavity (11); retracting each blocking piece (323) into the piston rod (31) by negative pressure of the pressure chamber (321).

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