A switchable vacuum and positive pressure induction melting furnace and its control method

Abstract

This invention relates to a switchable vacuum and positive pressure induction melting furnace and its control method. Both a vacuum pumping unit and a positive pressure charging unit are connected to the induction melting furnace. When either the vacuum pumping unit or the positive pressure charging unit is connected to the induction melting furnace via an interlocking unit, the other unit is simultaneously disconnected from the furnace via the same interlocking unit. A metal vapor capture unit is provided between the vacuum pumping unit and the induction melting furnace. The induction melting furnace is equipped with a furnace pressure detection component and a safety relief component, all of which are electrically connected to the control system. A crucible assembly is located within the melting chamber of the induction melting furnace, and an induction heating component is fitted around the crucible assembly. This invention enables both vacuum melting and positive pressure protective atmosphere melting, significantly improving the equipment's flexibility and applicability.

Description

Technical Field

[0001] This invention relates to the field of special metallurgical equipment, specifically to a switchable vacuum and positive pressure induction melting furnace and its control method. Background Technology

[0002] Vacuum induction melting typically involves placing the metal raw material in a sealed furnace or vacuum chamber, then using electromagnetic induction heating to raise the temperature, melt, and alloy the metal material in the crucible. This process can reduce the influence of gaseous elements such as oxygen, nitrogen, and hydrogen, as well as other impurities, on the molten metal, and is particularly suitable for the preparation of high-temperature alloys, nickel-based alloys, titanium alloys, special steels, and high-purity materials.

[0003] With the development of alloy systems and process routes, single vacuum melting furnaces are no longer sufficient to cover all operating conditions. For example, some metal materials are prone to volatilization loss under vacuum, while some processes require positive pressure melting, pressure holding, or pressure casting under high-purity argon, nitrogen, or other protective atmospheres. Therefore, this places higher demands on the design of vacuum melting furnaces, especially on the safe switching requirements between vacuum furnaces and positive pressure protective atmosphere furnaces.

[0004] The reason why existing vacuum induction melting furnaces or protective atmosphere induction melting furnaces cannot meet the above requirements is that:

[0005] 1. The vacuum pipeline and the positive pressure gas inlet pipeline lack reliable interlocking. Once an operation is misoperated, it will not only affect the state and quality of vacuum melting or positive pressure protective atmosphere melting, but also cause damage to the vacuum system or furnace body. In particular, high-temperature metal vapor, dust and other substances may enter the vacuum system and cause damage.

[0006] Second, the control requirements differ under different melting conditions. In vacuum melting, the vacuum level must meet the requirements, while in positive pressure protective atmosphere melting, the positive pressure protective gas pressure must meet the requirements. In addition, the charging height, molten pool depth, and melting temperature vary for different alloy materials and under different melting conditions, which further increases the difficulty of integrating vacuum melting and positive pressure protective atmosphere melting.

[0007] Thirdly, because the sealing force directions are different under vacuum and positive pressure conditions, ordinary sealing structures are generally difficult to adapt to repeated processes such as vacuuming, positive pressure filling, pressure increase, pressure holding, and high temperature cycling over a long period of time. Summary of the Invention

[0008] The purpose of this invention is to provide a switchable vacuum and positive pressure induction melting furnace and its control method, which can realize both vacuum melting and positive pressure protective atmosphere melting, thereby greatly improving the flexibility and applicability of the equipment.

[0009] The objective of this invention is achieved through the following technical solution:

[0010] A switchable vacuum and positive pressure induction melting furnace includes an induction melting furnace, a vacuum pumping unit, a positive pressure charging unit, a metal vapor capture unit, and an interlocking unit. Both the vacuum pumping unit and the positive pressure charging unit are connected to the induction melting furnace. When either the vacuum pumping unit or the positive pressure charging unit is connected to the induction melting furnace via the interlocking unit, the other unit is simultaneously disconnected from the induction melting furnace via the interlocking unit. A metal vapor capture unit is provided between the vacuum pumping unit and the induction melting furnace. The induction melting furnace is equipped with a furnace body pressure detection component and a safety pressure relief component, and all three components—the furnace body pressure detection component, the safety pressure relief component, the vacuum pumping unit, and the positive pressure charging unit—are electrically connected to a control system. A crucible assembly is provided inside the melting chamber of the induction melting furnace, and an induction heating component is fitted around the outside of the crucible assembly.

[0011] The vacuum pumping unit includes a vacuum pumping pipeline connected to the metal vapor capture unit, and the vacuum pumping pipeline is equipped with a vacuum pumping control element; the positive pressure charging unit includes a charging pipeline connected to the induction melting furnace, and the charging pipeline is equipped with a charging control element; the interlocking unit includes an interlocking seat, and the interlocking seat is equipped with a movable and adjustable interlocking valve block; both the vacuum pumping pipeline and the charging pipeline pass through the interlocking seat, and the interlocking valve block is equipped with a vacuum pumping channel as a vacuum pumping control element and a charging channel as a charging control element; when the vacuum pumping channel is connected to the vacuum pumping pipeline, the charging channel is offset from the charging pipeline and disconnected; when the charging channel is connected to the charging pipeline, the vacuum pumping channel is offset from the vacuum pumping pipeline and disconnected.

[0012] The vacuum pumping unit includes a vacuum pump assembly and a vacuum bypass. The vacuum pump assembly is connected to the metal vapor capture unit via a vacuum pipeline, and a vacuum pressure detection element is provided on the vacuum pipeline. One end of the vacuum bypass is connected to the vacuum pipeline on the input side of the vacuum control element, and the other end is connected to the vacuum pipeline on the output side of the vacuum pressure detection element. A bypass control element for controlling the on / off state is provided on the vacuum bypass.

[0013] The positive pressure inflation unit includes an air source, and the air source is connected to the induction melting furnace through an inflation pipeline; the inflation pipeline is provided with an inflation control element, a pressure stabilizing element, a one-way valve, an inflation pressure detection element, and a flow control element in sequence along the inflation direction.

[0014] One side of the interlock seat is provided with an interlock drive device for moving and adjusting the interlock valve block, and the other side is provided with a spring. The interlock valve block is provided with a limiting guide shaft, and the spring is sleeved on the limiting guide shaft.

[0015] The metal vapor capture unit includes a capture shell, one side of which is connected to the vacuum pipeline, and the other side is connected to the induction melting furnace through a pipeline. Inside the capture shell, along the gas outlet direction, there are sequentially arranged a water-cooling component, a condensation capture chamber, a capture net, a metal filter, and a ceramic filter. The water-cooling component includes water-cooling baffles connected in series.

[0016] The induction melting furnace includes a furnace body, and a sealed furnace cover is provided at the upper end of the furnace body. A furnace cover locking assembly is provided on the outside of the sealed furnace cover. A sealing element is provided between the sealed furnace cover and the furnace body.

[0017] The safety pressure relief assembly includes a pressure relief buffer chamber, an active pressure relief pipeline, and a passive pressure relief element. One end of the active pressure relief pipeline is connected to the pressure relief buffer chamber, and the other end is connected to a corresponding interface on the sealed furnace cover. The active pressure relief element is provided on the active pressure relief pipeline, and the passive pressure relief element is provided on the sealed furnace cover. The furnace body pressure detection assembly includes a vacuum pressure detection element, a transition pressure detection element, and a positive pressure detection element.

[0018] The induction heating assembly includes an induction power supply and a water-cooled induction coil. The induction power supply is electrically connected to multiple coil segment control modules. The water-cooled induction coil includes multiple coil heating segments, and each coil heating segment is controlled to heat through a corresponding coil segment control module. The induction heating assembly includes a coil water-cooling channel, with one end of the coil water-cooling channel connected to a coil inlet pipe and the other end connected to a coil return pipe. Each coil heating segment is connected to the coil water-cooling channel through a corresponding heating segment inlet pipe and heating segment return pipe.

[0019] A control method for the switchable vacuum and positive pressure induction melting furnace includes the following steps:

[0020] Step 1: Place the metal raw material into the induction melting furnace, and then turn off the induction melting furnace;

[0021] Step 2: After the control system detects that everything is normal, start the vacuum pumping unit to perform a vacuuming operation in the melting chamber of the induction melting furnace.

[0022] Step 3: Once the set vacuum level is reached inside the melting chamber of the induction melting furnace, the control system performs a vacuum holding test. If the vacuum holding status meets the requirements, proceed to the next stage.

[0023] Step 4: Based on the process requirements, select the control system as follows:

[0024] 1. The induction heating component is started in a vacuum state to perform vacuum melting. During vacuum melting, the melting chamber of the induction melting furnace is kept in a vacuum state by the vacuum pumping unit. The vacuum pumping unit prevents metal vapor from entering by the metal vapor trapping unit.

[0025] Second: Alternatively, the vacuum pumping unit can be turned off, and the positive pressure charging unit can be turned on to charge the melting chamber of the induction melting furnace with positive pressure protective gas to the set pressure. After the control system detects that the pressure is normal, the induction heating component can be started to melt under the positive pressure protective atmosphere. During the melting process, the melting chamber is maintained at pressure through the positive pressure charging unit and the safety pressure relief component. At the same time, the vacuum pumping unit is disconnected from the melting chamber through the interlocking unit to prevent positive pressure gas and metal vapor from entering the vacuum pumping unit.

[0026] The advantages and positive effects of this invention are as follows:

[0027] 1. This invention can achieve both vacuum melting and positive pressure protective atmosphere melting. Furthermore, this invention utilizes an interlocking unit to reliably switch between the vacuum pumping unit and the positive pressure charging unit. That is, when the vacuum pumping unit is working, the positive pressure charging unit is not activated; when the positive pressure charging unit is working, the vacuum pumping unit is not activated, thus not affecting the different melting states within the induction melting furnace.

[0028] 2. This invention not only enables vacuum melting and positive pressure protective atmosphere melting, but also meets the adjustment needs under different melting conditions. During vacuum melting, the vacuum extraction unit can be activated as needed to ensure the vacuum level within the furnace melting chamber meets requirements. Simultaneously, the metal vapor capture unit, through multi-stage capture, prevents metal vapor, dust, etc., from entering the vacuum extraction unit and causing damage. During melting under a positive pressure protective atmosphere, the positive pressure charging unit can supplement gas as needed, and the safety pressure relief component can release pressure as needed, thereby ensuring the gas pressure within the furnace melting chamber meets requirements. Simultaneously, the vacuum extraction unit is disconnected from the melting chamber via the interlocking unit, thus preventing positive pressure gas and metal vapor from entering the vacuum extraction unit.

[0029] 3. The induction heating component of the present invention uses water-cooled induction coil heating, and the water-cooled induction coil further includes multiple coil heating sections. Each coil heating section can be controlled to heat independently, or they can work together to achieve zone heating. This greatly improves the flexibility of melting heating control, so that the induction heating component can meet the different heating needs of the induction melting furnace under different melting states.

[0030] 4. The furnace body pressure detection assembly of the present invention includes multiple pressure detection elements corresponding to different melting states of the induction melting furnace. The control system selects the corresponding pressure detection element for pressure detection according to the different states of the induction melting furnace, thereby ensuring the accuracy of pressure detection and control under different states. The vacuum pressure detection element is used to detect the pressure during vacuum melting, the positive pressure detection element is used to detect the pressure during positive pressure protective atmosphere melting, and the transition pressure detection element is used to detect the pressure in the furnace body melting chamber when transitioning from a vacuum state to a normal pressure or positive pressure state.

[0031] 5. The present invention provides a sealed furnace cover at the upper end of the furnace body of the induction melting furnace, and a furnace cover locking assembly is provided on the outside of the sealed furnace cover. In addition, only a single sealing element is provided between the sealed furnace cover and the furnace body. The sealing is mainly ensured by the closing locking force of the sealed furnace cover and the furnace body through the furnace cover locking assembly. This can reduce the number of sealing layers and connecting branches, and can meet the sealing requirements of long-term repeated vacuuming, positive pressure gas filling, pressure increase, pressure holding and high temperature cycling. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the physical structure of the present invention.

[0033] Figure 2 for Figure 1 A schematic diagram illustrating the structural principle of the present invention.

[0034] Figure 3 for Figure 2 An enlarged schematic diagram of the furnace lid.

[0035] Figure 4 for Figure 2 A connection diagram of the medium vacuum pumping unit, positive pressure charging unit, safety pressure relief assembly, and furnace body pressure detection assembly.

[0036] Figure 5 for Figure 4 A schematic diagram of the structure of a medium-sized metal vapor capture unit.

[0037] Figure 6 for Figure 4 A schematic diagram of the interlocking unit structure between the medium vacuum pumping unit and the positive pressure inflation unit.

[0038] Figure 7 for Figure 2 A schematic diagram of the internal structure of the furnace body.

[0039] Figure 8 for Figure 7 A schematic diagram of the structure of the induction heating component when a segmented water-cooled induction coil is used.

[0040] Among them, 1 is an induction melting furnace, 101 is the furnace body, 1011 is the lower sealing mating surface, 102 is the sealed furnace cover, 1021 is the upper sealing mating surface, 103 is the sealed base, 104 is the furnace body cooling assembly, 105 is the furnace body pressure detection assembly, 1051 is the vacuum pressure detection element, 1052 is the transition pressure detection element, 1053 is the positive pressure detection element, 106 is the safety pressure relief assembly, 1061 is the active pressure relief element, 1062 is the passive pressure relief element, 1063 is the pressure relief buffer chamber, 107 is the furnace cover locking assembly, and 108 is the sealing element; 2 is the control system; 3 is the metal vapor capture unit, 301 is the water-cooled baffle, 302 is the condensation capture chamber, 303 is the capture net, 304 is the metal filter element, 305 is the ceramic filter element, and 306 is the discharge port; 4 is the crucible assembly, 401 is... The components are: crucible (402 is crucible base); induction heating assembly (501 is induction power supply, 5011 is coil section control module, 502 is coil water inlet pipe, 503 is coil water return pipe, 504 is coil water cooling channel, 505 is coil heating section); vacuum pumping unit (601 is vacuum pump set, 602 is vacuum pipeline, 603 is vacuum control element, 604 is vacuum bypass, 605 is vacuum pressure detection element); positive pressure charging unit (701 is gas source, 702 is voltage stabilizing element, 703 is flow control element, 704 is one-way valve, 705 is charging control element, 706 is charging pressure detection element, 707 is charging pipeline); and interlocking unit (801 is interlock seat, 802 is interlock drive device, 803 is interlock valve block, 804 is spring, and 805 is limit guide shaft). Detailed Implementation

[0041] The invention will now be described in further detail with reference to the accompanying drawings.

[0042] like Figures 1-8 As shown, the present invention includes an induction melting furnace 1, a vacuum pumping unit 6, a positive pressure charging unit 7, a metal vapor capture unit 3, and an interlocking unit 8, wherein the vacuum pumping unit 6 and the positive pressure charging unit 7 are both connected to the induction melting furnace 1, and as shown... Figure 6 As shown, the vacuum pumping unit 6 and the positive pressure charging unit 7 are controlled to switch connections via an interlocking unit 8. When the vacuum pumping unit 6 is connected to the induction melting furnace 1 via the interlocking unit 8, the positive pressure charging unit 7 is simultaneously disconnected from the induction melting furnace 1 via the interlocking unit 8. Figure 4 As shown, a metal vapor capture unit 3 is provided between the vacuum pumping unit 6 and the induction melting furnace 1. The metal vapor capture unit 3 is used to capture and intercept impurities such as metal dust and condensed particles in the high-temperature steam inside the furnace, thereby protecting the vacuum pumping unit 6; Figure 2 As shown, the induction melting furnace 1 is equipped with a furnace body pressure detection component 105 and a safety pressure relief component 106, such as... Figure 4 As shown, the furnace body pressure detection component 105, safety pressure relief component 106, vacuum pumping unit 6, and positive pressure charging unit 7 are all electrically connected to the control system 2.

[0043] like Figure 4 As shown, in this embodiment, the vacuum pumping unit 6 includes a vacuum pump assembly 601, and the vacuum pump assembly 601 is connected to the metal vapor capture unit 3 via a vacuum pipeline 602. The metal vapor capture unit 3 is connected to the induction melting furnace 1. The positive pressure charging unit 7 includes a gas source 701 and a charging pipeline 707 connected in sequence, and the charging pipeline 707 is connected to the induction melting furnace 1. The vacuum pipeline 602 is provided with a vacuum control element 603, and the charging pipeline 707 is provided with a charging control element 705. Figure 6 As shown, in this embodiment, the vacuum control element 603 and the gas filling control element 705 are both integrated into the interlocking unit 8.

[0044] like Figure 6 As shown, in this embodiment, the interlocking unit 8 includes an interlocking seat 801, and the interlocking seat 801 is provided with an adjustable interlocking valve block 803; the vacuuming pipeline 602 and the inflation pipeline 707 both pass through the interlocking seat 801, and the interlocking valve block 803 is provided with a vacuuming channel as a vacuuming control element 603 and an inflation channel as an inflation control element 705; when the vacuuming channel is connected to the vacuuming pipeline 602, the inflation channel is offset from the inflation pipeline 707 and disconnected; conversely, when the inflation channel is connected to the inflation pipeline 707, the vacuuming channel is offset from the vacuuming pipeline 602 and disconnected.

[0045] like Figure 6As shown, in this embodiment, one side of the interlock seat 801 is provided with an interlock drive device 802 for driving the interlock valve block 803 to move and adjust. The interlock drive device 802 can be a linear drive device such as a cylinder as needed. The other side of the interlock seat 801 is provided with a spring 804 that abuts against the interlock valve block 803, which is used to realize the automatic reset and elastic buffer of the interlock valve block 803. One side of the interlock valve block 803 is provided with a limiting guide shaft 805, and the spring 804 is sleeved on the limiting guide shaft 805. In addition, the present invention can provide slide rails on both inner walls of the interlock seat 801 as needed. The interlock valve block 803 has concave sliding grooves on both sides that cooperate with the corresponding slide rails, thereby realizing the sliding connection between the interlock valve block 803 and the interlock seat 801 and ensuring the linear movement of the interlock valve block 803. The cooperation between the concave sliding grooves and the slide rails can ensure that the inner wall of the interlock seat 801 is in contact with the outer wall of the interlock valve block 803, thereby ensuring a seal. At the same time, a sealing element (such as a density pad) can be provided on the interlock valve block 803 as needed to slide and fit against the inner wall of the interlock seat 801 to further ensure the sealing performance.

[0046] The reason for using the above-mentioned mechanical interlock unit 8 in this embodiment is that the structure does not rely on PLC program logic and can eliminate the possibility of simultaneous opening of the vacuum pipeline 602 and the gas charging pipeline 707 from the mechanical action level, thereby ensuring the reliability of the interlock. It is especially suitable for the induction melting furnace 1 in the case of frequent switching between vacuum melting and positive pressure protective atmosphere melting.

[0047] The present invention can also achieve electrical control interlocking of vacuuming line 602 and inflation line 707 through circuit design as needed, or achieve interlocking control of vacuuming line 602 and inflation line 707 through other means.

[0048] like Figure 2 and Figure 4 As shown, in this embodiment, the vacuum pumping unit 6 has a vacuum pressure detection element 605 on its vacuum pumping pipeline 602. The vacuum pumping unit 6 also includes a vacuum bypass 604. One end of the vacuum bypass 604 is connected to the vacuum pumping pipeline 602 on the input side of the vacuum control element 603, and the other end is connected to the vacuum pumping pipeline 602 on the output side of the vacuum pressure detection element 605. The vacuum bypass 604 is equipped with a bypass control element for controlling the on / off state, such as a bypass control valve, which is a commercially available product. In this embodiment, the vacuum bypass 604 is used to open the connection for auxiliary control during the initial vacuuming stage or pressure transition phase. Furthermore, in this embodiment, the vacuum pump group 601 can use a rotary vane pump, dry pump, Roots pump, or other pump body as needed. The vacuum pressure detection element 605 is used to detect the vacuum level inside the induction furnace 1, and can use a resistance vacuum gauge, thermocouple vacuum gauge, or other components as needed. All of the above pump bodies and components are commercially available products.

[0049] like Figure 2 and Figure 4 As shown, in this embodiment, the inflation pipeline 707 of the positive pressure inflation unit 7 is sequentially equipped with an inflation control element 705, a pressure stabilizing element 702, a one-way valve 704, an inflation pressure detection element 706, and a flow control element 703. The pressure stabilizing element 702 is used to regulate the pressure of the protective gas entering the induction melting furnace 1. The one-way valve 704 is used to prevent gas or metal vapor in the induction melting furnace 1 from flowing back into the gas source 701. The flow control element 703 is used to control the flow rate of the gas entering the induction melting furnace 1. In this embodiment, the pressure stabilizing element 702 can be a pressure stabilizing valve, and the flow control element 703 can be a flow meter; both are commercially available products. Furthermore, in this embodiment, the protective gas in the gas source 701 can be argon, nitrogen, helium, or other protective gases. When used for easily oxidized materials such as titanium alloys and high-temperature alloys, high-purity argon is preferred.

[0050] like Figure 5 As shown, in this embodiment, the metal vapor capture unit 3 includes a capture shell, one side of which is connected to the vacuum pipe 602, and the other side is connected to the induction melting furnace 1 via a pipe. Inside the capture shell, along the gas outlet direction, are sequentially arranged a water-cooling assembly, a condensation capture chamber 302, a capture net 303, a metal filter element 304, and a ceramic filter element 305. The water-cooling assembly includes water-cooling baffles 301 connected in series, with the first water-cooling baffle 301 connected to a water-cooling inlet pipe and the last water-cooling baffle 301 connected to a water-cooling outlet pipe. The components are used to reduce the temperature of the high-temperature gas and metal vapor output from the induction melting furnace 1. After the temperature is reduced, the gas or metal vapor enters the condensation and collection chamber 302 to condense and deposit, thereby achieving preliminary filtration of impurities in the gas. Then, the collection net 303 intercepts metal dust and condensed particles that have not been condensed and deposited. The metal filter element 304 and the ceramic filter element 305 are used to further block solid particles. The metal filter element 304 can adopt the same metal mesh structure as the collection net, but its mesh is smaller and denser. The ceramic filter element 305 is further provided with through holes with smaller diameters to block small solid particles.

[0051] like Figure 5As shown, in this embodiment, the collection housing is provided with a discharge port 306 with a control valve for discharging residual gas or impurities inside the housing. Additionally, the collection net 303 has a detachable structure; for example, the collection housing has mounting tracks on both the upper and lower sides, and the collection net 303 is slidably inserted into the corresponding mounting tracks on the upper and lower sides. A maintenance door is provided on one side of the collection housing; opening the door allows the collection net 303 to be pulled out for replacement. The metal filter element 304 and the ceramic filter element 305 can also adopt the aforementioned removable structure, that is, the upper and lower sides of the metal filter element 304 and the upper and lower sides of the ceramic filter element 305 are slidably inserted into the corresponding mounting tracks. This not only facilitates replacement and maintenance but also allows for flexible selection of combinations of the collection net 303, metal filter element 304, ceramic filter element 305, or other filter elements according to actual needs.

[0052] Furthermore, a gas purification device can be further installed on the inflation pipeline 707 of the positive pressure inflation unit 7 as needed. This gas purification device can be at least one of a deaerator, a water separator, and a particulate filter, thus reducing the oxygen, moisture, and particulate content in the protective gas as required. The deaerator, water separator, and particulate filter are all technologies known in the art and are commercially available products.

[0053] like Figure 2 As shown, in this embodiment, the induction melting furnace 1 includes a furnace body 101, and the furnace body 101 has a sealing base 103 at its lower end and a sealing furnace cover 102 at its upper end. A furnace cover locking assembly 107 is provided on the outer side of the sealing furnace cover 102. The furnace cover locking assembly 107 can adopt a suitable structure as needed. For example, it can adopt a mechanical locking structure of bolts and nuts, where the bolt passes through the furnace cover flange and the furnace body flange and is threadedly connected to the nut. In this way, the furnace cover is locked by the clamping action of the bolt and the nut. Alternatively, it can adopt an upper and lower clamping plate structure, where the upper and lower clamping plates are automatically closed and moved by pneumatic, electric or hydraulic means, thereby clamping the furnace cover flange and the furnace body flange to achieve locking.

[0054] like Figure 2 As shown, the sealed furnace cover 102 can be equipped with an observation window for observing the internal condition of the furnace body 101 as needed. Simultaneously, the sealed furnace cover 102 can also be equipped with various interfaces as needed, including temperature measurement interfaces, feeding interfaces, spare interfaces, and detection interfaces. Unused interfaces can be blocked with plugs to ensure the internal sealing of the furnace body 101. And as... Figure 3As shown, in this embodiment, a sealing element 108 is provided between the sealed furnace cover 102 and the furnace body 101 to ensure a seal. The lower side of the sealed furnace cover 102 has a sealing upper fitting surface 1021 that mates with the sealing element 108, and the upper side of the furnace body 101 has a sealing lower fitting surface 1011 that mates with the sealing element 108. The sealing element 108 can be a sealing ring or similar component. This invention provides only a single sealing element 108 between the sealed furnace cover 102 and the furnace body 101, and the sealing element 108 primarily ensures a seal through the closing locking force of the furnace cover 102 and the furnace body 101 via the furnace cover locking assembly 107. This reduces the number of sealing layers and connecting branches, while also meeting the sealing requirements of long-term repeated vacuuming, positive pressure gas filling, pressurization, pressure holding, and high-temperature cycling processes.

[0055] like Figure 2 and Figure 4 As shown, in this embodiment, the furnace pressure detection assembly 105 includes a vacuum pressure detection element 1051, a transition pressure detection element 1052, and a positive pressure detection element 1053. The vacuum pressure detection element 1051 detects the pressure in the vacuum zone (i.e., the vacuum melting state) within the furnace body 101. The transition pressure detection element 1052 detects the pressure during the transition from a vacuum state to atmospheric pressure or a positive pressure state within the furnace body 101. The positive pressure detection element 1053 detects the pressure during the positive pressure melting stage within the furnace body 101. Since the pressure differences between different states of the induction melting furnace 1 are relatively large, the control system 2 of this invention selects the corresponding pressure detection element for pressure detection according to the different states of the induction melting furnace 1. This ensures the accuracy of pressure detection and control. All of the above pressure detection elements can be commercially available products such as pressure sensors.

[0056] like Figure 2 and Figure 4As shown, in this embodiment, the safety pressure relief assembly 106 includes a pressure relief buffer chamber 1063, an active pressure relief pipeline, and a passive pressure relief element 1062. One end of the active pressure relief pipeline is connected to the pressure relief buffer chamber 1063, and the other end is connected to a corresponding interface on the sealed furnace cover 102. An active pressure relief element 1061 is provided on the active pressure relief pipeline, and the passive pressure relief element 1062 is provided on the sealed furnace cover 102. In this embodiment, the active pressure relief element 1061 can be an electrically controlled pressure relief valve. When the pressure detected by any pressure detection element in the furnace body pressure detection assembly 105 exceeds the set safety pressure, the control system 2 controls the electrically controlled pressure relief valve to open, thereby reducing the pressure in the melting chamber of the furnace body 101. The passive pressure relief element 1062 can be in the form of a rupture disc or a mechanical safety valve. When the active pressure relief element 1061 fails or the pressure rises too quickly, the gas can rupture the rupture disc or mechanical safety valve to achieve passive pressure relief. The electrically controlled pressure relief valve, rupture disc, and mechanical safety valve mentioned are all technologies known in the art and are commercially available products.

[0057] like Figure 2 and Figure 7 As shown, in this embodiment, a crucible assembly 4 is provided inside the melting chamber of the furnace body 101, and an induction heating assembly 5 is sleeved on the outside of the crucible assembly 4. During operation, the metal material is placed on the crucible assembly 4 and melted by the induction heating assembly 5. Figure 7 As shown, in this embodiment, the crucible assembly 4 includes a crucible 401 and a crucible base 402. The crucible 401 can be selected from alumina crucible, magnesium oxide crucible, zirconium oxide crucible, graphite crucible, boron nitride crucible, water-cooled copper crucible, or coated crucible, depending on the furnace material.

[0058] like Figure 7 As shown, in this embodiment, the induction heating component 5 includes an induction power supply 501 and a water-cooled induction coil. One end of the cooling channel of the water-cooled induction coil is connected to the coil inlet pipe 502, and the other end is connected to the coil return pipe 503. The heating coil inside the water-cooled induction coil is electrically connected to the induction power supply 501. The water-cooled induction coil is a known technology in the art; for example, see patents such as CN206340688U.

[0059] like Figure 8As shown, in order to achieve a wider temperature regulation range to adapt to the smelting needs of different smelting states, different charging heights, different molten pool depths, and different alloy materials, the water-cooled induction coil of this invention can adopt a segmented design. That is, the water-cooled induction coil includes multiple coil heating sections 505, and the induction power supply 501 is electrically connected to multiple coil section control modules 5011. Each coil heating section 505 is controlled for heating by a corresponding coil section control module 5011, thereby enabling independent heating or coordinated zone heating. In addition, the induction heating assembly 5 includes a coil water-cooling channel 504, one end of which is connected to the coil water inlet pipe 502, and the other end is connected to the coil water return pipe 503. The coil heating sections 505 are respectively connected to the coil water-cooling channel 504 through corresponding heating section water inlet pipes and heating section water return pipes.

[0060] Other examples Figure 2 As shown, in this embodiment, the furnace body 101 has a furnace body water cooling cavity in its inner wall, the sealed furnace cover 102 has a furnace cover water cooling cavity inside, and the furnace body water cooling cavity, the furnace cover water cooling cavity and the water-cooled induction coil are all supplied with water through the furnace body cooling assembly 104.

[0061] In this embodiment, the furnace body water-cooling cavity has a first water inlet pipe on one side and a first water return pipe on the other side. The furnace cover water-cooling cavity has a second water inlet pipe on one side and a second water return pipe on the other side. The furnace body cooling assembly 104 includes a main water inlet pipe and a main water return pipe. The coil water inlet pipe 502, the first water inlet pipe, and the second water inlet pipe are all connected to the main water inlet pipe. The coil water return pipe 503, the first water return pipe, and the second water return pipe are all connected to the main water return pipe. Water flow detection elements, water pressure detection elements, water temperature detection elements, etc., can be installed on the main water inlet pipe and the main water return pipe as needed. When the cooling water flow is insufficient, the water pressure is abnormal, or the water temperature exceeds the set value, the control system 2 can reduce the output power of the induction power supply 501 or stop the operation of the induction heating assembly 5. The water flow detection elements, water pressure detection elements, water temperature detection elements, etc., are all technologies known in the art and are commercially available products. For example, flow meters, pressure gauges, temperature sensors, etc., can be used.

[0062] The working principle of this invention is as follows:

[0063] like Figures 1-8 As shown, the working process of this invention is as follows:

[0064] Step 1: Open the sealed furnace cover 102 and put the metal raw material into the crucible 401 in the melting chamber of the furnace body 101. Then close the sealed furnace cover 102 and use the furnace cover locking assembly 107 to lock the furnace body 101 and the furnace cover 102.

[0065] Step 2: Control system 2 checks whether the status of each unit is normal. After the check is normal, control vacuum pumping unit 6 starts to perform vacuuming operation in the melting chamber inside furnace body 101.

[0066] Step 3: When the melting chamber inside the furnace body 101 reaches the set vacuum level, the control system 2 performs a vacuum maintenance test. If the vacuum maintenance status meets the requirements, the next stage will begin.

[0067] In this step, the control system 2 determines whether the vacuum maintenance status meets the requirements by detecting the pressure value or pressure change rate in the melting chamber of the furnace body 101.

[0068] Step 4: Based on the process requirements, control system 2 makes the following selections:

[0069] 1. Initiate vacuum melting by activating the induction heating component 5 under vacuum conditions;

[0070] Second: Alternatively, turn off the vacuum pumping unit 6 and turn on the positive pressure charging unit 7 to charge the furnace body 101 melting chamber with positive pressure protective gas to the set pressure. Then, after the control system 2 detects that the status of each unit is normal, it starts the induction heating component 5 to carry out melting under positive pressure protective atmosphere.

[0071] During vacuum melting, the vacuum pumping unit 6 can be activated as needed to ensure that the vacuum level in the melting chamber of the furnace 101 meets the requirements. At this time, the high-temperature gas in the melting chamber of the furnace 101 may contain metal vapor formed by volatile elements. The metal vapor capture unit 3 can prevent metal vapor from entering the vacuum pumping unit 6 through multi-stage capture.

[0072] During melting under a positive pressure protective atmosphere, the positive pressure gas supply unit 7 can supplement gas as needed, or the safety pressure relief component 106 can relieve pressure as needed, so that the gas pressure in the melting chamber of the furnace body 101 meets the requirements. After melting is completed, the control system 2 controls the safety pressure relief component 106 to open so that the melting chamber of the furnace body 101 is depressurized to a safe state, and then the furnace cover 102 is opened to remove the casting or crucible 401.

[0073] like Figure 6 As shown, this invention utilizes interlocking unit 8 to achieve reliable switching interlock between vacuum pumping unit 6 and positive pressure charging unit 7. That is, when vacuum pumping unit 6 is working, positive pressure charging unit 7 is not activated, and when positive pressure charging unit 7 is working, vacuum pumping unit 6 is not activated, thus not affecting the different melting states within induction melting furnace 1. And as... Figure 8 As shown, the induction heating component 5 of the present invention can be heated by a water-cooled induction coil including multiple coil heating sections 505. Each coil heating section 505 can be controlled to heat independently or cooperate to achieve zone heating, which can further meet the heating needs of the induction melting furnace 1 under different melting states.

Claims

1. A switchable vacuum and positive pressure induction melting furnace, characterized in that: The system includes an induction melting furnace (1), a vacuum pumping unit (6), a positive pressure charging unit (7), a metal vapor capture unit (3), and an interlocking unit (8). The vacuum pumping unit (6) and the positive pressure charging unit (7) are both connected to the induction melting furnace (1). When either the vacuum pumping unit (6) or the positive pressure charging unit (7) is connected to the induction melting furnace (1) via the interlocking unit (8), the other unit is simultaneously disconnected from the induction melting furnace (1) via the interlocking unit (8). (6) A metal vapor capture unit (3) is provided between the induction melting furnace (1); the induction melting furnace (1) is provided with a furnace body pressure detection component (105) and a safety pressure relief component (106), and the furnace body pressure detection component (105), the safety pressure relief component (106), the vacuum pumping unit (6) and the positive pressure charging unit (7) are all electrically connected to the control system (2); the melting chamber of the induction melting furnace (1) is provided with a crucible assembly (4), and the crucible assembly (4) is fitted with an induction heating component (5) on the outside.

2. The switchable vacuum and positive pressure induction melting furnace according to claim 1, characterized in that: The vacuum pumping unit (6) includes a vacuum pumping pipeline (602) connected to the metal vapor capture unit (3), and a vacuum control element (603) is provided on the vacuum pumping pipeline (602); the positive pressure gas filling unit (7) includes a gas filling pipeline (707) connected to the induction melting furnace (1), and a gas filling control element (705) is provided on the gas filling pipeline (707); the interlocking unit (8) includes an interlocking seat (801), and an interlocking valve block (803) that can be moved and adjusted is provided inside the interlocking seat (801); the vacuum pumping unit (6) includes a vacuum pumping pipeline (602) connected to the metal vapor capture unit (3), and a vacuum control element (603) is provided on the vacuum pumping pipeline (602); the positive pressure gas filling unit (7) includes a gas filling pipeline (707) connected to the induction melting furnace (1), and a gas filling control element (705) is provided on the gas filling pipeline (707); the positive pressure gas filling unit (8) includes an interlocking seat (801), and a positive pressure gas filling unit (802) includes an interlocking seat (801), and a positive pressure gas filling unit (702 ... Both the empty pipeline (602) and the inflation pipeline (707) pass through the interlock seat (801), and the interlock valve block (803) is provided with a vacuuming channel as a vacuuming control element (603) and an inflation channel as an inflation control element (705); when the vacuuming channel is connected to the vacuuming pipeline (602), the inflation channel is staggered from the inflation pipeline (707) and disconnected; when the inflation channel is connected to the inflation pipeline (707), the vacuuming channel is staggered from the vacuuming pipeline (602) and disconnected.

3. The switchable vacuum and positive pressure induction melting furnace according to claim 2, characterized in that: The vacuum pumping unit (6) includes a vacuum pump group (601) and a vacuum bypass (604). The vacuum pump group (601) is connected to the metal vapor capture unit (3) through a vacuum pipeline (602), and a vacuum pressure detection element (605) is provided on the vacuum pipeline (602). One end of the vacuum bypass (604) is connected to the vacuum pipeline (602) on the input side of the vacuum control element (603), and the other end is connected to the vacuum pipeline (602) on the output side of the vacuum pressure detection element (605). A bypass control element for controlling the on / off state is provided on the vacuum bypass (604).

4. The switchable vacuum and positive pressure induction melting furnace according to claim 2, characterized in that: The positive pressure charging unit (7) includes a gas source (701), and the gas source (701) is connected to the induction melting furnace (1) through a charging pipeline (707); the charging pipeline (707) is provided with a charging control element (705), a pressure stabilizing element (702), a one-way valve (704), a charging pressure detection element (706), and a flow control element (703) in sequence along the charging direction.

5. The switchable vacuum and positive pressure induction melting furnace according to claim 2, characterized in that: The interlock seat (801) has an interlock drive device (802) on one side that drives the interlock valve block (803) to move and adjust, and a spring (804) inside the other side. The interlock valve block (803) is provided with a limiting guide shaft (805), and the spring (804) is sleeved on the limiting guide shaft (805).

6. The switchable vacuum and positive pressure induction melting furnace according to claim 1, characterized in that: The metal vapor capture unit (3) includes a capture shell, and one side of the capture shell is connected to the vacuum pipeline (602), and the other side is connected to the induction melting furnace (1) through a pipeline; the inside of the capture shell is provided with a water cooling component, a condensation capture chamber (302), a capture net (303), a metal filter (304) and a ceramic filter (305) in sequence along the gas outlet direction, wherein the water cooling component includes water cooling baffles (301) connected in series end to end.

7. The switchable vacuum and positive pressure induction melting furnace according to claim 1, characterized in that: The induction melting furnace (1) includes a furnace body (101), and a sealing furnace cover (102) is provided at the upper end of the furnace body (101). A furnace cover locking assembly (107) is provided on the outside of the sealing furnace cover (102); a sealing element (108) is provided between the sealing furnace cover (102) and the furnace body (101).

8. The switchable vacuum and positive pressure induction melting furnace according to claim 7, characterized in that: The safety pressure relief assembly (106) includes a pressure relief buffer chamber (1063), an active pressure relief pipeline, and a passive pressure relief element (1062). One end of the active pressure relief pipeline is connected to the pressure relief buffer chamber (1063), and the other end is connected to the corresponding interface on the sealed furnace cover (102). The active pressure relief element (1061) is provided on the active pressure relief pipeline, and the passive pressure relief element (1062) is provided on the sealed furnace cover (102). The furnace body pressure detection assembly (105) includes a vacuum pressure detection element (1051), a transition pressure detection element (1052), and a positive pressure detection element (1053).

9. The switchable vacuum and positive pressure induction melting furnace according to claim 1, characterized in that: The induction heating assembly (5) includes an induction power supply (501) and a water-cooled induction coil. The induction power supply (501) is electrically connected to multiple coil segment control modules (5011). The water-cooled induction coil includes multiple coil heating segments (505), and each coil heating segment (505) is heated by a corresponding coil segment control module (5011). The induction heating assembly (5) includes a coil water-cooling channel (504), and one end of the coil water-cooling channel (504) is connected to the coil water inlet pipe (502), and the other end is connected to the coil water return pipe (503). The coil heating segments (505) are connected to the coil water-cooling channel (504) through corresponding heating segment water inlet pipes and heating segment water return pipes.

10. A control method for a switchable vacuum and positive pressure induction melting furnace according to claim 1, characterized in that: Includes the following steps: Step 1: Place the metal raw material into the induction melting furnace (1), and then turn off the induction melting furnace (1). Step 2: After the control system (2) detects that everything is normal, it controls the vacuum pumping unit (6) to start the vacuum pumping operation in the melting chamber of the induction melting furnace (1); Step 3: When the set vacuum level is reached inside the melting chamber of the induction melting furnace (1), the control system (2) performs vacuum maintenance detection. If the vacuum maintenance status meets the requirements, the next stage is entered. Step 4: Based on the process requirements, the control system (2) makes the following selections:

1. The induction heating component (5) is started in a vacuum state to perform vacuum melting. During vacuum melting, the melting chamber of the induction melting furnace (1) is kept in vacuum by the vacuum pumping unit (6). The vacuum pumping unit (6) prevents metal vapor from entering by the metal vapor trapping unit (3).

2. Alternatively, the vacuum pumping unit (6) can be turned off and the positive pressure charging unit (7) can be turned on to charge the positive pressure protective gas into the melting chamber of the induction melting furnace (1) to the set pressure. Then, after the control system (2) detects that it is normal, the induction heating component (5) is started to melt under the positive pressure protective atmosphere. During the melting process, the melting chamber is maintained by the positive pressure charging unit (7) and the safety pressure relief component (106). At the same time, the vacuum pumping unit (6) is disconnected from the melting chamber by the interlocking unit (8) to prevent the positive pressure gas and metal vapor from entering the vacuum pumping unit (6).

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