Metal material supply device

Abstract

A metal material supply device (30) provided in conjunction with a metal melting furnace (10) has a vibration tank (54) that conveys a metal material to be supplied to a crucible (11). The conveyed metal material is discharged from a material discharge port (57) provided at a front end portion of the vibration tank (54). The metal material supply device (30) is movable between a material supply position in which the material discharge port (57) is disposed above the crucible (11) and a retreated position retreated from the material supply position, and thus is capable of supplying the metal material to the crucible (11) at the material supply position. An upper end portion of the metal material supplied to the crucible (11) and accumulated thereon is detected by a microwave level meter (71), and a material supply operation performed by driving the vibration tank (54) is controlled on the basis of a detection value thereof.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to Japanese Application No. 2020-039789, filed on March 9, 2020, the contents of which are incorporated herein by reference. Technical Field

[0003] This invention relates to a metal material supply device for supplying metal materials to a metal melting furnace. Background Technology

[0004] In casting, where molten metal is poured into a mold to create a casting, a metal melting furnace is used to melt the metal material. Induction furnaces are commonly used, where an induced current is generated in the metal material within the crucible to heat it (see, for example, Patent Document 1).

[0005] A metal material supply device is provided together with the metal melting furnace. This device measures the amount of metal material required for each casting and supplies it to the crucible. By providing a metal material supply device, a casting cycle consisting of metal material supply, metal material heating, and transfer of molten metal is established (see Patent Document 1).

[0006] Patent Document 1: Japanese Patent Application Publication No. 2003-164960

[0007] Even when metal is added to the crucible, it does not melt instantly; melting takes time. Therefore, if the supply of metal from the metal supply device to the crucible is not based on the melting state of the metal in the crucible, the necessary amount of metal cannot be supplied when needed, resulting in wasted power consumption in the induction furnace and becoming a significant factor leading to increased costs. Summary of the Invention

[0008] Therefore, the object of the present invention is to provide a metal material supply device that can supply metal materials to a metal melting furnace in a timely and efficient manner.

[0009] To address the aforementioned issues, the first invention provides a metal material supply device, which is installed together with a metal melting furnace. This metal material supply device comprises:

[0010] The material conveying unit conveys the metal material to be supplied to the crucible of the aforementioned metal melting furnace;

[0011] A material discharge port is provided at the end of the aforementioned material conveying section to discharge the aforementioned metal material conveyed by the aforementioned material conveying section.

[0012] The moving mechanism moves the material conveying unit between a material supply position where the material outlet is positioned above the crucible and the metal material is supplied to the crucible, and a retracted position from the material supply position.

[0013] The materials inspection department inspects the accumulation status of the metal material supplied to and accumulated within the crucible; and

[0014] The material conveying control unit controls the material conveying operation of the material conveying unit based on the detection values ​​of the material detection unit.

[0015] In the second invention, the material detection unit detects the height of the upper end of the metal material piled in the crucible.

[0016] In the third invention, if the above-mentioned detection value is detected within a specified range for a specified period of time, the material conveying control unit determines that the metal material accumulated in the crucible is in a hanging state, and stops the material conveying operation of the material conveying unit.

[0017] In the fourth invention, the material detection unit described above includes:

[0018] The detection subject transmits microwaves and receives the reflected waves of the aforementioned microwaves; and

[0019] A hollow antenna with an opening facing downwards in the vertical direction illuminates microwaves transmitted from the detection subject downwards through the opening and guides reflected waves into the opening.

[0020] The aforementioned detection unit is located above the aforementioned material conveying section.

[0021] In the fifth invention, a gas supply unit is provided that supplies gas to the interior of the hollow antenna so that the gas is discharged from the opening of the hollow antenna.

[0022] In the sixth invention, the metal material supply device includes:

[0023] The opening and closing plate opens and closes the outlet for the aforementioned materials; and

[0024] An arm rotation mechanism rotates the support arm that supports the opening and closing plate, moving it to a closed position that closes the material outlet and to an open position that is positioned above the material outlet and opens the material outlet.

[0025] The aforementioned detection body is positioned behind the aforementioned opening / closing plate, which is located at the aforementioned open position.

[0026] In the seventh invention, the hollow antenna extends vertically in front of the material outlet and has the opening at its lower end.

[0027] The aforementioned opening and closing plate is suspended and supported between the aforementioned material outlet and the aforementioned hollow antenna, and is able to rotate relative to the suspension shaft that extends in the left and right direction when viewed from the front of the aforementioned material outlet.

[0028] A locking part is provided in front of the aforementioned opening and closing plate, which locks the rotation of the opening and closing plate before it rotates forward and collides with the aforementioned hollow antenna.

[0029] According to the first invention, by confirming the condition of the metal material supplied to and accumulated in the crucible, such as the height and shape of the accumulation, and by temporarily stopping the material conveying and supplying operation when an unfavorable condition arises, and controlling the resumption of the material conveying and supplying operation when the condition improves, material supply corresponding to the condition of the metal material in the crucible can be automatically performed. Therefore, metal material can be supplied to the crucible in a timely and efficient manner, thereby reducing the cost required for melting the metal material.

[0030] According to the second invention, the condition of the metal material piled in the crucible can be detected by detecting the height of the upper end of the piled metal material. If the pile height is to be detected, the condition can be easily detected using a distance sensor or similar device. Furthermore, if a distance sensor or similar device is used, it can be subsequently installed on an existing metal material supply device, thus reducing the cost increase of the metal material supply device.

[0031] According to the third invention, the displacement of the material height is monitored, and the conveying of the metal material is stopped when it is determined that the accumulated metal material is in a hanging state. This prevents the occurrence of missed hanging abnormalities, which could lead to an abnormal rise in temperature inside the crucible of the metal melting furnace and cause various adverse conditions.

[0032] According to the fourth invention, when the material conveying unit is positioned at the material supply location, the detection body of the material detection unit is isolated from the metal melting furnace, and the material conveying unit is sandwiched between them, thereby shielding the radiant heat emitted from the metal melting furnace from the material conveying unit. This protects the detection body from the effects of radiant heat.

[0033] According to the fifth invention, when the material conveying unit is positioned at the material supply position and the material detection unit is positioned above the crucible, the gas supplied to the interior of the hollow antenna is discharged downwards from the opening of the hollow antenna. This prevents smoke and dust rising from the crucible from entering the opening of the hollow antenna and accumulating inside, thus suppressing any negative impact on microwave transmission and the introduction of reflected waves.

[0034] According to the sixth invention, a closing plate is provided for opening and closing the material discharge port. Therefore, by closing the material discharge port with the closing plate when the material conveying operation has stopped, material supply can be prevented from accidentally falling out. Furthermore, a detection body for the material detection unit is positioned rearward of the closing plate when it is in the open position. Therefore, when the material conveying unit is positioned in the material supply position, moving the closing plate to the open position blocks radiant heat emitted from the metal melting furnace. Thus, the closing plate also functions to protect the detection body from radiant heat.

[0035] According to the seventh invention, when the opening / closing plate moves between the closed and open positions by rotating the support arm, if the rotatable opening / closing plate, which is suspended and supported, intends to rotate forward, its rotation is stopped by the locking part. This prevents the opening / closing plate from colliding with the hollow antenna of the material detection unit and damaging the hollow antenna during rotation. Attached Figure Description

[0036] The above-mentioned objects, other objects, features and advantages of the present invention will become clearer from the following detailed description with reference to the accompanying drawings.

[0037] Figure 1 This is a side view showing a metal material supply device.

[0038] Figure 2 This is an enlarged side view showing the opening and closing mechanism of the discharge port.

[0039] Figure 3 This is a three-dimensional diagram representing the opening and closing mechanism of the discharge outlet.

[0040] Figure 4 It is a block diagram representing the electrical structure of a metal material supply device.

[0041] Figure 5 This is a flowchart representing the material supply control process. Detailed Implementation

[0042] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0043] like Figure 1As shown, the metal material supply device 30 is provided together with the metal melting furnace 10. The metal melting furnace 10 is an induction heating type melting furnace, having a crucible 11 and an induction coil 12. The crucible 11 is a bottomed cylindrical container with an opening 11a at its upper end facing upwards. Metal material is supplied into the crucible 11 through the opening 11a. The supplied metal material is heated and melts inside, becoming molten metal. The molten metal accumulates inside the crucible 11. The induction coil 12 is arranged around the cylindrical portion surrounding the crucible 11. An alternating current flows through the induction coil 12, thereby induction heating the metal material supplied into the crucible 11.

[0044] An inlet 11b is provided at the upper end of the crucible 11. The inlet 11b protrudes to the side from the opening 11a. The crucible 11 has a tilting mechanism (not shown) that tilts the crucible 11. When the crucible 11 is tilted by the tilting mechanism, the molten metal accumulated inside the crucible 11 is transferred from the inlet 11b to the casting container (not shown).

[0045] The metal material supply device 30 is configured to supply metal material to the crucible 11 of the aforementioned metal melting furnace 10. For example... Figure 1 As shown, the metal material supply device 30 is configured such that the upper surface of the movable worktable 21 of the metal material supply device 30 can move in one direction ( Figure 1 The metal material supply device 30 moves in the direction of approaching the metal melting furnace 10 (left and right). Figure 1 (to the right) and the direction of retreat and separation from the metal melting furnace 10 ( Figure 1 The metal material supply device 30 moves between the left and right sides. In the following description, the direction of movement of the metal material supply device 30 is defined as the device movement direction, the direction of approaching the metal melting furnace 10 is defined as forward, and the direction of separation from the metal melting furnace 10 is defined as backward. Figure 1 In the diagram, a metal material supply device 30 that moves backward and is positioned in a rearward position is shown in solid lines. On the other hand, a front end of the metal material supply device 30 that moves forward and is positioned in a material supply position is shown in dashed lines.

[0046] On the upper surface of the movable worktable 21, viewed from the direction of movement of the metal material supply device 30, there are two guide grooves 22, one on each side, along the direction of movement, to guide the movement of the metal material supply device 30. The height of the upper surface of the movable worktable 21 is the same as the height of the upper end of the metal melting furnace 10. As a result, metal material can be supplied from the metal material supply device 30 to the opening 11a of the crucible 11 from above the opening 11a.

[0047] The metal material supply device 30 is generally configured to have a device base 32 and a material supply section 33. The device base 32 supports the material supply section 33, which holds a metered amount of metal material and conveys it toward the material discharge port 57.

[0048] The device base 32 has a rectangular base frame 41 when viewed from above. The base frame 41 has a total of four wheels 42 and 43, including a pair of front wheels 42 and a pair of rear wheels 43. The wheels 42 and 43 are arranged in one row on each side when viewed from the direction of movement of the device. Figure 1 This is a side view, thus showing one front wheel 42 and one rear wheel 43. Furthermore, the number of wheels 42 and 43 is arbitrary. The wheels 42 and 43, arranged in the left and right columns, engage with guide grooves 22 provided on the upper surface of the movable worktable 21. The device base 32 can move along the guide grooves 22 in the device's moving direction via the wheels 42 and 43. Alternatively, instead of guide grooves 22, guide rails can be provided on the upper surface of the movable worktable 21, and the wheels 42 and 43 can be placed on these guide rails.

[0049] The base 32 of the device has a moving drive device 34. The moving drive device 34 has a drive source mainly composed of an electric motor, and drives a pair of rear wheels 43 located at the rear as drive wheels. Driven by the rear wheels 43, the metal material supply device 30 moves along the moving direction of the device. The moving mechanism that moves the metal material supply device 30 consists of a guide groove 22, wheels 42 and 43, and the moving drive device 34.

[0050] The material supply unit 33 is mounted on the device base 32. The material supply unit 33 has a hopper 51 and a material delivery unit 52.

[0051] The hopper 51 is a container for storing metal materials, and its upper part is open. When the metal material supply device 30 is in the retracted position, a pre-set amount of metal material is fed into the open upper part of the hopper 51 and contained within the hopper 51. The metal material contained in the hopper 51 falls out from the lower opening provided at the lower end of the hopper 51. The hopper 51 is mounted on the device base 32 via a support frame 53 erected on the base frame 41.

[0052] The material feeding section 52 is located below the hopper 51. The material feeding section 52 is a vibrating conveyor, which has the function of feeding metal materials supplied to the hopper 51. The material feeding section 52 includes: a vibrating trough 54, an excitation device 55, an anti-vibration spring 56, a discharge port opening and closing mechanism 58, a microwave level 71, and an empty detection sensor 79.

[0053] Vibration groove 54 is a roughly U-shaped flow channel when viewed from the direction of device movement (see reference). Figure 3The vibrating trough 54 is configured to extend from below the lower opening of the hopper 51 to its front. Metal material falling from the lower opening of the hopper 51 is placed on the inner bottom surface 54a of the vibrating trough 54. The front end of the vibrating trough 54 protrudes forward beyond the front end of the device base 32. The vibrating trough 54 slopes downward from the rear to the front, with the front side lower than the rear side. The excitation device 55 is configured as an electric motor, positioned below the hopper 51 within the vibrating trough 54. Operation of the excitation device 55 causes the vibrating trough 54 to vibrate, thereby conveying the metal material placed on the inner bottom surface 54a of the vibrating trough 54 forward. The vibrating trough 54 functions as a material conveying section.

[0054] The anti-vibration spring 56 is a helical spring that supports the vibration groove 54 with elastic vertical displacement relative to the base frame 41 of the device base 32. The anti-vibration spring 56 is respectively provided at the front end and the rear end of the base frame 41.

[0055] The front end of the vibrating trough 54 opens forward, and its opening becomes the material discharge port 57. Metal material conveyed forward by the vibration of the vibrating trough 54 is discharged from the material discharge port 57. The discharged metal material falls downward from the material discharge port 57. If the metal material supply device 30 moves to the material supply position, the material discharge port 57 is positioned above the opening 11a of the crucible 11, thereby enabling the supply of metal material. In this position, if metal material is discharged from the material discharge port 57 and falls, it is supplied into the interior of the crucible 11.

[0056] Figure 2 The enlarged view of the microwave level 71 is omitted. As shown in the figure, the outlet opening and closing mechanism 58 is provided near the material outlet 57 for opening and closing the material outlet 57. The outlet opening and closing mechanism 58 has an opening and closing plate 61, a pair of support arms 62, and an arm rotation mechanism 64.

[0057] like Figure 2 as well as Figure 3 As shown, the opening / closing plate 61 abuts against the periphery of the material discharge port 57 to close the material discharge port 57. This state is the closed state, and the position of the opening / closing plate 61 is set to the closed position. A pair of ribs 61a are provided on the front surface of the opening / closing plate 61 for reinforcement. When the opening / closing plate 61 is positioned in the closed position, causing the material discharge port 57 to be closed, it is possible to prevent metal material from being discharged from the material discharge port 57. Furthermore, when the opening / closing plate 61 is in the closed state, the vibration of the vibration groove 54 also stops.

[0058] One support arm 62 is provided on each side when viewed from the direction of movement of the device. Figure 1 and Figure 2 This is a side view, therefore only one side of the support arm 62 is shown in both figures. Figure 2 and Figure 3 As shown, a pair of support arms 62 extend at an angle from the rear to the front, with the front side lower than the rear side. At the front ends of the two support arms 62, a suspension shaft 63 for suspending the opening and closing plate 61 is provided between the two support arms 62. The suspension shaft 63 is in a direction orthogonal to the direction of movement of the device (with...). Figure 2 The direction (orthogonal to the paper surface) extends to the left and right when viewing the material outlet 57 from the front. An opening / closing plate 61 is suspended and supported on the hanging shaft 63 in a manner that allows it to rotate around its axial direction. In this case, the opening / closing plate 61 is positioned in the closed position.

[0059] like Figure 2 As shown, an arm rotation mechanism 64 is provided on the rear end side of each support arm 62. The arm rotation mechanism 64 has an arm rotation shaft 65 extending in a direction orthogonal to the movement direction of the device and a rotation drive source 66 for the arm rotation shaft 65. The arm rotation shaft 65 is rotatably mounted on a rotation support portion 67 provided in the vibration groove 54, and each support arm 62 is connected to the arm rotation shaft 65 in a non-rotatable manner. The rotation drive source 66 is a cylinder, and a linkage mechanism 68 is provided to rotate the arm rotation shaft 65 by the movement of the cylinder rod 66a.

[0060] By rotating the drive source 66, such as Figure 2 As shown, a pair of support arms 62 rotate synchronously around the arm rotation axis 65. With the opening / closing plate 61 in the closed position, as described above, the pair of support arms 62 tilt downwards from the rear to the front. If the pair of support arms 62 are rotated from this state to a horizontal position, the hanging shaft 63 moves upwards in an arc. Figure 2 Based on this reference, the pair of support arms 62 rotate to the left. Through the rotation of the support arms 62, the rotatable opening / closing plate 61, suspended by the hanging shaft 63, follows along, maintaining its suspended state by its own weight, and is positioned diagonally above the material discharge port 57. The material discharge port 57 is in the open state when it is open; its position is set to the open position. If the opening / closing plate 61 is positioned in the open position, causing the material discharge port 57 to be open, metal material can be discharged from the material discharge port 57.

[0061] An extension portion 62a, slightly extending from the front end, is integrally provided at the front end of each support arm 62 where the hanging shaft portion 63 is located. Each extension portion 62a is configured to form a V-shape with the support arm 62. For example... Figure 2 as well as Figure 3As shown, a locking rod 69 extending horizontally is mounted between the two extensions 62a and in front of the opening / closing plate 61. When the opening / closing plate 61 moves between the closed and open positions due to the rotation of the two support arms 62, if the opening / closing plate 61 attempts to rotate forward, its rotation is stopped by the locking rod 69, thereby preventing further forward rotation. This maintains the opening / closing plate 61 hanging vertically from the hanging shaft 63. The locking rod 69 corresponds to a locking part.

[0062] return Figure 1 The microwave level 71 measures the height of the metal material that is placed into and piled on the opening 11a of the crucible 11. The microwave level 71 functions as a material detection unit. Unlike lasers and ultrasound, microwaves pass through smoke and dust rising from the opening 11a of the crucible 11 without being reflected, thus providing stable measurement values. The microwave level 71 includes a level body 72, a waveguide 73, and a hollow antenna 74.

[0063] The level body 72 generates microwaves and receives reflected waves to measure the level (height) of the metallic material. The level body 72 is equivalent to the detection body. A leveling plate 75 is provided on the front side of the vibration groove 54, behind the material outlet 57 and above the vibration groove 54. The level body 72 is mounted on this leveling plate 75. When the opening / closing plate 61 for opening and closing the material outlet 57 is in the open position, the opening / closing plate 61 is positioned diagonally below the leveling plate 75. The level body 72 is housed in a housing 76 made of heat-resistant material.

[0064] Waveguide 73 transmits microwaves from level body 72 to hollow antenna 74, and transmits reflected waves guided into hollow antenna 74 back to level body 72. Waveguide 73 protrudes forward from the front surface of level body 72 and bends 90 degrees forward of the front end of vibration groove 54 where material outlet 57 is provided, so that the front end faces downward in the vertical direction.

[0065] The hollow antenna 74 is a truncated cone-shaped horn antenna, with its small-diameter portion mounted at the front end of the waveguide 73. The hollow antenna 74 extends vertically forward of the opening / closing plate 61 and the locking rod 69 that open and close the material outlet 57. The lower end of the hollow antenna 74 has an expanded diameter, forming a downward-facing waveguide opening 77 in the vertical direction. When viewed from the direction of device movement, the hollow antenna 74 is positioned at the left or right center of the rectangular material outlet 57. Furthermore, if the metal material supply device 30 is positioned at the material supply position, the central axis C of the hollow antenna 74, including the center of the waveguide opening 77, coincides with the central axis C of the opening 11a of the crucible 11. Alternatively, the hollow antenna 74 may also be truncated pyramidal in shape, etc.

[0066] Microwaves emitted from the level body 72 are irradiated downwards from the waveguide opening 77 after passing through the waveguide 73. Furthermore, the reflected waves generated by the irradiated microwaves being reflected by the object being measured below are guided into the waveguide opening 77 and then transmitted back to the level body 72 via the waveguide 73. The microwave level 71 measures the distance between the top (upper end) of the deposited metal material and the waveguide opening 77.

[0067] Purge air is introduced into the hollow antenna 74 via waveguide 73. An air compressor 78 is mounted at the rear end of the device base 32. Compressed air generated by the air compressor 78 is delivered from the air supply piping (not shown) through the waveguide 73 to the interior of the hollow antenna 74. The delivered compressed air is discharged downwards from the waveguide opening 77 as purge air. The air compressor 78, the air supply piping, and the waveguide 73 constitute the gas supply section.

[0068] The empty detection sensor 79 is a laser-type distance sensor, mounted on the mounting plate 75 above the microwave level 71, behind the microwave level 71. The empty detection sensor 79 measures the distance between itself and a location slightly behind the material discharge port 57. This measurement result is used to determine whether all the metal material has been supplied from the vibrating trough 54 to the crucible 11, thus emptying the vibrating trough 54.

[0069] Next, the electrical structure of the metal material supply device 30 will be explained. For example... Figure 4 As shown, the metal material supply device 30 includes a control device 81. The control device 81 includes a device control unit 82, a storage unit 83, an information input unit 84 (such as a keyboard), and a display unit 85 (such as a liquid crystal monitor). The device control unit 82 is a microcomputer composed of a CPU or similar component, and functions as a material delivery control unit. The device control unit 82 is connected to the storage unit 83, the information input unit 84, and the display unit 85, respectively.

[0070] The device control unit 82 is also connected to the motion drive unit 34, the excitation device 55, the rotation drive source 66 of the arm rotation shaft 65 in the discharge port opening and closing mechanism 58, the air compressor 78, the microwave level 71, and the air detection sensor 79. The device control unit 82 controls the movement of the metal material supply device 30, the conveying of the metal material in the vibration tank 54, and the opening and closing of the material discharge port 57 by controlling the drive of each of these devices. When supplying metal material to the opening 11a of the crucible 11, the material height value detected by the microwave level 71 and the distance measurement value from the air detection sensor 79 are sequentially input into the device control unit 82.

[0071] The storage unit 83 stores the implementation program for control processing performed by the device control unit 82, the upper and lower limits of the material height, the monitoring time for material hanging abnormalities, and the judgment value for material hanging abnormalities. The upper and lower limits of the material height, the monitoring time for material hanging abnormalities, and the judgment value for material hanging abnormalities can be arbitrarily set using the information input unit 84 and the setting screen displayed on the display unit 85, respectively. The material height values ​​sequentially input from the microwave level 71 are also stored in the storage unit 83.

[0072] Here, the "material hanging state" is a state commonly known as a problem that may occur when materials are melted in the furnace. It refers to a state in which metal material, while melting in the crucible 11, hangs on the furnace wall and remains there, forming a lid-like structure. The condition is defined as being in a "material hanging state" if the displacement of the material height exceeds the material hanging anomaly detection value (e.g., 5 mm) for more than the material hanging anomaly monitoring time (e.g., 60 seconds) and persists.

[0073] The information input unit 84 and the display unit 85 can use known devices that have the above-mentioned functions. For example, they can be button-type input devices and displays, or touch panel displays that combine the functions of both.

[0074] Next, based on Figure 5 The flowchart describes the material supply control process performed by the device control unit 82 of the control device 81. Furthermore, at the start of this control process, the metal material supply device 30 is in the retracted position, and metal material has already been supplied to the hopper 51.

[0075] like Figure 5As shown, in step S101, the driving device 34 moves the metal material supply device 30 from the retracted position to the forward position, stopping it at the material supply position. At the material supply position, the waveguide opening 77 of the hollow antenna 74 of the microwave level 71 is positioned on the central axis of the crucible 11. Furthermore, the material discharge port 57 is positioned above the opening 11a of the crucible 11, further rearward than the hollow antenna 74. At this time, the air compressor 78 is simultaneously driven to introduce purge air into the waveguide 73 of the microwave level 71, causing purge air to discharge downwards from the waveguide opening 77.

[0076] In the next step S102, the metal material supply process begins. During this process, the rotation drive 66 of the arm rotation shaft 65 in the discharge port opening / closing mechanism 58 is driven, causing the support arm 62 to rotate and the opening / closing plate 61 to be positioned in the open position, opening the material discharge port 57. If the opening / closing plate 61 attempts to rotate forward along with the rotation of the support arm 62, its rotation is stopped by the locking rod 69, thus preventing collision with the hollow antenna 74. Simultaneously, the excitation device 55 is driven, causing the vibration groove 54 to vibrate and convey the metal material forward. Thus, the metal material falls from the material discharge port 57 and begins to be supplied into the crucible 11.

[0077] In the next step S103, based on the detection result of the material height of the metal material piled in the crucible 11, it is determined whether the material height exceeds the upper limit value. If it does not exceed the upper limit value, it is determined as negative, and the process proceeds to step S104.

[0078] In step S104, based on the detection result of the material height of the metal material, it is determined whether a material hanging abnormality has occurred. In this case, if the displacement of the material height exceeds the material hanging abnormality monitoring time within the range of the material hanging abnormality determination value and persists, it is determined that a material hanging state has occurred. If it is determined that no material hanging abnormality has occurred, the determination is negative, and the process proceeds to the next step S105.

[0079] In step S105, based on the distance measurement results to the near portion of the material discharge port 57, it is determined whether all the metal material has been supplied to the crucible 11 and the vibration tank 54 is empty. If there is metal material in the near portion of the material discharge port 57, since the supply of metal material has not been completed, it is determined to be negative, and the process returns to the previous step S103. On the other hand, if it is determined that there is no metal material from the vibration tank 54 and the vibration tank 54 is empty, it is determined to be positive, and the process proceeds to step S106.

[0080] In step S106, a metal material supply stop process is performed. During this process, the rotation drive source 66 of the discharge port opening / closing mechanism 58 rotates the support arm 62 in the opposite direction, positioning the opening / closing plate 61 in the closed position to close the material discharge port 57. If the opening / closing plate 61 attempts to rotate forward along with the rotation of the support arm 62, its rotation is stopped by the locking rod 69, preventing collision with the hollow antenna 74. The closed state of the opening / closing plate 61 over the material discharge port 57 is then maintained. Simultaneously, the drive of the excitation device 55 is stopped, thus halting the material conveying operation. After stopping the material conveying operation and closing the material discharge port 57, the drive movement drive device 34 moves the metal material supply device 30 from the material supply position to the retracted position. The process then ends.

[0081] Through the above process, while the material height does not exceed the upper limit and the vibration groove 54 is not empty but contains residual metal material, the opening and closing plate 61 is kept in the open position, and the excitation device 55 continues to be driven to continue supplying metal material to the crucible 11. Then, if all the metal material has been supplied to the crucible 11 and the vibration groove 54 becomes empty, the process ends.

[0082] On the other hand, in the previous step S103, if the material height exceeds the upper limit, it is determined to be positive, and the process proceeds to step S107. In step S107, a temporary halt to the supply of metal material is performed. In the temporary halt to the supply process, the same process as the supply halt process in step S106 described above is executed.

[0083] Next, in step S108, based on the detection result of the material height of the metal material piled in the crucible 11, it is determined whether the material height exceeds the lower limit. If it does not exceed the lower limit, it is determined as negative, and the determination is repeated until the material height exceeds the lower limit. During this period, the supply of metal material is temporarily stopped. On the other hand, if it exceeds the lower limit, it is determined as positive, and the process proceeds to the next step S109.

[0084] In step S109, a metal material supply recovery process is performed. This recovery process is the same as the supply initiation process in step S102. As a result, the metal material falls from the material discharge port 57, resuming the supply to the crucible 11. Afterwards, the process proceeds to step S104, which determines whether a material buildup abnormality has occurred. Subsequent processes are as described above.

[0085] Furthermore, in the previous step S104, if an abnormality in material adhesion was determined to have occurred, the process was confirmed and proceeded to step S110. In step S110, a temporary halt to the supply of metal material was performed. This temporary halt involved the same process as the supply halt in step S106 described above.

[0086] In the next step S111, it is determined whether the material hanging abnormality has been eliminated. The operation to eliminate the material hanging abnormality is performed by an operator; therefore, the operator who has completed the abnormality elimination operation uses the information input unit 84 and the display unit 85 to perform an abnormality completion operation. If this abnormality completion operation is not performed, since the abnormality elimination operation has not been performed, the determination is negative, and the determination is repeated until the abnormality completion operation is performed. During this period, the supply of metal material is temporarily stopped. Then, if the operator performs the abnormality completion operation, the determination is positive, and the process returns to the previous step S105. Subsequent processing is as described above.

[0087] As detailed above, the metal material supply device 30 according to this embodiment can achieve the following effects.

[0088] (1) When operators visually confirm the accumulation of metal material supplied to crucible 11, the resumption of material supply is often delayed because they also have to perform other tasks besides material input. In this case, the efficiency of supplying metal material to crucible 11 deteriorates, and correspondingly, the electricity required for heating by induction coil 12 increases, becoming a significant factor in cost increase. In this regard, in the metal material supply device 30 of this embodiment, the material height of the metal material supplied to crucible 11 is detected by microwave level 71. If the detected value exceeds the upper limit, the material supply operation is temporarily stopped; if it exceeds the lower limit, the material supply operation is automatically resumed. As a result, metal material can be supplied to crucible 11 in a timely and efficient manner, thereby reducing costs.

[0089] (2) The height of the upper end of the metal material accumulated in the crucible 11 is detected by using a microwave level 71, thereby detecting the accumulation status. By using a microwave level 71 as a distance sensor, the accumulation status can be easily detected. In addition, since the microwave level 71 is used, it can also be installed on an existing metal material supply device, thus suppressing the increase in cost of the metal material supply device 30.

[0090] (3) The displacement of the material height is monitored, thereby detecting the occurrence of abnormal material hanging. In the event of abnormal material hanging, the supply of metal material is temporarily stopped, thereby preventing the occurrence of abnormal material hanging, which would lead to an abnormal rise in temperature inside the crucible 11 of the metal melting furnace 10 and thus cause various adverse situations.

[0091] (4) The level body 72 of the microwave level 71 is positioned rearward of the material outlet 57 and above the vibration groove 54. Not only is the level body 72 isolated from the metal melting furnace 10, but the vibration groove 54 is also sandwiched between them, thus shielding the radiant heat emitted from the metal melting furnace 10 from the vibration groove 54. This protects the level body 72 from radiant heat. Furthermore, since the level body 72 is housed in a housing 76 made of heat-resistant material, it is further protected from radiant heat.

[0092] (5) When the metal material supply device 30 is positioned at the material supply location and the microwave level 71 is positioned above the opening 11a of the crucible 11, purge air is introduced into the waveguide 73 of the microwave level 71 and discharged downwards from the waveguide opening 77. This prevents smoke and dust rising from the opening 11a of the crucible 11 from entering the waveguide opening 77 and accumulating inside the hollow antenna 74, thus suppressing any negative impact on microwave transmission and the introduction of reflected waves.

[0093] (6) A discharge outlet opening and closing mechanism 58 is provided near the material discharge outlet 57, and the material discharge outlet 57 is opened and closed by an opening and closing plate 61. Therefore, if material supply is temporarily stopped due to the height of the metal material exceeding the upper limit, closing the material discharge outlet 57 by the opening and closing plate 61 can prevent the metal material from falling and allow material supply to continue. Furthermore, a level body 72 of a microwave level 71 is positioned behind the opening and closing plate 61, thus shielding the radiant heat emitted from the metal melting furnace 10 from the opening and closing plate 61. Therefore, the opening and closing plate 61 also serves to protect the level body 72 from radiant heat.

[0094] (7) In the outlet opening and closing mechanism 58, the opening and closing plate 61 is supported by the hanging shaft 63 so that it can rotate, and a locking rod 69 is provided in front of the opening and closing plate 61. When the opening and closing plate 61 moves between the closed position and the open position by the rotation of the two support arms 62, if the opening and closing plate 61 wants to rotate forward, its rotation is stopped by the locking rod 69, thereby preventing it from colliding with the hollow antenna 74 and damaging the hollow antenna 74.

[0095] Furthermore, the present invention is not limited to the metal material supply device 30 of the above embodiment, and may also adopt a structure as follows.

[0096] (a) In the above embodiment, a microwave level 71 was used as the material detection unit. Alternatively, a level utilizing electromagnetic waves such as millimeter waves can also be used. Furthermore, the condition of the metal material accumulated in the crucible 11 can be detected by methods other than detecting the material height. For example, it is possible to capture the shape of the metal material accumulation using an image, thereby detecting the condition of the metal material.

[0097] (b) In the above embodiment, the metal material supply device 30 is moved by using the rear wheel 43 provided on the device base 32 as the drive wheel. Instead, the moving mechanism of the metal material supply device 30 can be, for example, configured to allow the trolley with wheels to move by any combination of known structures, such as a structure that connects the device base 32 to the rod of the hydraulic cylinder and allows the rod to move in and out.

[0098] (c) In the above embodiment, in the arm rotation mechanism 64, the rotation drive source 66 that rotates the support arm 62 is a cylinder. As the rotation drive source 66, an electric motor or the like may also be used, for example.

[0099] (d) In the above embodiment, the material feeding unit 52 includes a vibrating groove 54, which is vibrated by an excitation device 55, thereby conveying the metal material to the material discharge port 57. A conveyor belt can also be used as the material feeding mechanism. Furthermore, in the case of using a vibrating groove 54 or a conveyor belt, the conveying surface may not be inclined as in the above embodiment, but rather formed as a horizontal surface.

[0100] (e) In the above embodiment, a PLC (Programmable Logic Controller) may also be used as the device control unit 82.

[0101] (f) In the above embodiment, various information is stored in the storage unit 83, which is provided separately from the device control unit 82. However, if a microcomputer with internal memory is used as the device control unit 82, such as the PLC described above, the storage unit 83 may be omitted. In addition, it is not necessary to store the material height value input sequentially from the microwave level 71 in the storage unit 83 each time.

[0102] (g) In the above embodiment, compressed air is first introduced into the waveguide 73, and then supplied to the interior of the hollow antenna 74 through the waveguide 73. Alternatively, compressed air may be supplied directly to the hollow antenna 74. In this case, the gas supply unit is constituted by the air compressor 78 and the air supply piping.

[0103] Although the invention has been described with reference to embodiments, it should be understood that the invention is not limited to those embodiments or constructions. The invention also includes various modifications and variations within the same scope. Furthermore, various combinations and forms, and even other combinations and forms that include only one element, or include one or more elements, are also within the scope and spirit of the invention.

[0104] Explanation of reference numerals in the attached figures

[0105] 10…Metal melting furnace; 11…Crucible; 30…Metal material supply device; 54…Vibration trough (material conveying section); 57…Material discharge port; 61…Opening and closing plate; 62…Support arm; 63…Hanging shaft; 64…Arm rotation mechanism; 68…Clamping rod (Clamping part); 71…Microwave level (material detection section); 72…Level body (detection body); 73…Waveguide (gas supply section); 74…Hollow antenna; 77…Waveguide opening (opening); 78…Air compressor (gas supply section); 82…Device control section (material conveying control section).

Claims

1. A metal material supply device, which is installed together with a metal melting furnace, The metal material supply device is characterized by comprising: a material supply unit, a device base, a moving mechanism, and a material conveying control unit. The material supply unit includes: a vibrating trough for conveying metal material to be supplied to a crucible in the metal melting furnace; a material discharge port disposed at the end of the vibrating trough for discharging the metal material conveyed by the vibrating trough; and a material detection unit including: a detection body disposed above the vibrating trough for transmitting microwaves and receiving reflected waves of the microwaves; and a hollow antenna with an opening facing downward in the vertical direction, irradiating microwaves transmitted from the detection body downward through the opening and guiding reflected waves into the opening, wherein the material detection unit detects the height of the upper end of the metal material supplied to the crucible and accumulated in the crucible; The base of the device houses the material supply unit and is movable between a direction approaching the metal melting furnace and a direction retracting and separating from the metal melting furnace. The moving mechanism moves the vibrating trough between a material supply position where the material outlet is positioned above the crucible and capable of supplying the metal material to the crucible, and a retracted position after retracting from the material supply position. The material conveying control unit controls the material conveying action of the vibrating trough based on the detection values ​​of the material detection unit.

2. The metal material supply device according to claim 1, characterized in that, If the detected value is within a specified range for a specified period of time, the material conveying control unit determines that the metal material accumulated in the crucible is in a hanging state, and stops the material conveying action of the vibrating trough.

3. The metal material supply device according to claim 1 or 2, characterized in that, The device includes a gas supply unit that supplies gas to the interior of the hollow antenna so that the gas can be discharged from the opening of the hollow antenna.

4. The metal material supply device according to claim 1 or 2, characterized in that, have: An opening and closing plate that opens and closes the material discharge port; and An arm rotation mechanism rotates the support arm that supports the opening and closing plate, moving it to a closed position that closes the material outlet and to an open position that is positioned above the material outlet and opens the material outlet. The detection body is positioned behind the opening / closing plate at the open position.

5. The metal material supply device according to claim 4, characterized in that, The hollow antenna extends vertically in front of the material outlet and has an opening at its lower end. The opening and closing plate is suspended and supported between the material outlet and the hollow antenna, and is able to rotate relative to the suspension shaft that extends in the left and right direction when viewed from the front of the material outlet. A locking part is provided in front of the opening and closing plate, which locks the rotation of the opening and closing plate before the opening and closing plate rotates forward and collides with the hollow antenna.

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