baking equipment

Abstract

To provide a baking device that can ensure safety when a high-temperature baking object (7) descends after baking is completed and can be removed. [Solution] The system comprises a heating means 1 for heating the material 7 to be fired in a furnace 14, an in-furnace thermocouple 4 for measuring the temperature inside the furnace 14, a hearth 8 on which the material 7 to be fired is placed, a drive means for moving the hearth 8 from the furnace 14 downward to a work area 26, a door 17 covering the work area 26, a locking mechanism 19 provided in the housing for locking the door 17, and a lock control unit for controlling the locking mechanism 19; after heating of the material 7 to be fired is completed, the lock control unit releases the locking mechanism 19 when the material 7 to be fired has dropped to a predetermined temperature.

Description

[Technical Field]

[0001] The present invention relates to a firing apparatus for sintering an object by heating, and more particularly to a dental firing apparatus for firing a prosthesis or the like. [Background technology]

[0002] Patent Document 1 discloses a firing apparatus in which the opening of the combustion chamber is opened and closed by raising and lowering a vertically lowered furnace door, and the area where the furnace door is lowered is an open space. A placement area for cooling the workpiece is provided at a position away from the opening of the combustion chamber. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-192799 Summary of the Invention [Problem to be solved by the invention]

[0004] However, immediately after firing is complete, the inside of the furnace and the objects to be fired are at high temperatures, and if the furnace door is opened immediately after firing, the heat inside the furnace will leak into the work area, forcing workers to remove the objects at high temperatures. [Means for solving the problem]

[0005] In view of the above problems, the baking device according to the present invention is a heating means for heating the object to be fired in the furnace; a furnace thermocouple for measuring the temperature inside the furnace; A hearth on which the object to be fired is placed; a drive means for moving the hearth from the furnace downwardly to a work area; a door covering the work area; a locking mechanism provided in the housing for locking the door; a lock control unit that controls the lock mechanism; and After the heating of the baking object is completed, when the baking object has dropped to a predetermined temperature, the lock control unit releases the lock mechanism. [Effects of the Invention]

[0006] According to the present invention, the denture can be removed after firing has been completed when the temperature has dropped to a safe level. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a side cross-sectional view illustrating a baking device of the present invention. [Figure 2] FIG. 10 is a side cross-sectional view illustrating the operation of the baking device of the present invention. [Figure 3] FIG. 10 is a side cross-sectional view illustrating the operation of the baking device of the present invention. [Figure 4] FIG. 1 is a diagram illustrating the configuration of a control device according to the present invention. [Figure 5] FIG. 1 is a flowchart illustrating the present invention. [Figure 6] FIG. 10 is a flowchart illustrating a second embodiment of the present invention. [Figure 7] FIG. 10 is a flowchart illustrating a third embodiment of the present invention. [Figure 8] FIG. 10 is a rear view illustrating the configuration of the third embodiment of the present invention. [Figure 9] FIG. 10 is a flowchart illustrating a fourth embodiment of the present invention. [Figure 10] FIG. 10 is a schematic cross-sectional view illustrating the configuration of Example 4 of the present invention. [Figure 11] FIG. 1 is a flowchart illustrating the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0008] Example 1 A side cross-sectional view of a dental baking apparatus according to the present invention is shown in Figure 1. The dental baking apparatus 13 comprises a heater 1 for heating a furnace chamber 14, side insulation 2 and top insulation 3 surrounding the furnace chamber 14, a stage 9 for loading and unloading a prosthesis 7 to be baked in the baking apparatus into and out of the furnace chamber 14, an elevator 12 (driving means) for moving and raising and lowering the stage, a work area 26 located below the furnace chamber 14 where the prosthesis 7 to be baked is placed on and removed from the stage 9, and a door 17 for covering the work area 26.

[0009] In the present invention, a hinge is provided below the door 17, and opening the door 17 in a downward direction allows access to the work area 26. Furthermore, to lock the door 17, there is an actuator 19, which is a locking mechanism, on the door 17 side, and an electromagnetic lock 20 with a solenoid function that electrically locks and unlocks the door on the work area 26 side; the door can be locked by closing it and inserting the actuator 19 into the electromagnetic lock 20.

[0010] Heater 1 uses a resistance heating element such as molybdenum disilicide, silicon carbide, or carbon, and molybdenum disilicide heaters are often used to fire zirconia, which has become a popular material for prosthesis 7 in recent years. The heater is typically shaped like a rod and then bent into a U-shape, W-shape, or coil. Power is supplied to the heater via electric wire 11 from a power source (not shown), and it is heated to a temperature appropriate for the material of prosthesis 7. Firing zirconia typically took 7 to 8 hours in the past, but recent material developments have led to the development of materials that can be fired in less than 90 minutes.

[0011] The temperature of the furnace chamber is detected by an in-furnace thermocouple 4, and the heater temperature is controlled according to a preset heating program. Materials that can withstand high temperatures, such as platinum, platinum-rhodium, or a tungsten-rhenium alloy, are used for the in-furnace thermocouple 4, but this is not limited to these. In the present invention, to reduce positional variation in the tip of the in-furnace thermocouple 4, it is placed in a ceramic protective tube made of alumina or the like and fixed to the top heat insulating material 3.

[0012] It is more preferable that the tip of the in-furnace thermocouple 4 be disposed close to the prosthesis 7 without coming into contact with the prosthesis 7 so that the temperature in the vicinity of the prosthesis 7 can be detected.

[0013] The prosthesis 7 is placed on the dental baking device 13 with the stage 9 lowered and the door 17 open as shown in FIG.

[0014] When the prosthesis 7 is placed on the firing table 8, which is the hearth on the stage 9, and the door 17 is closed, the stage 9 is raised by the elevator 12 and the prosthesis 7 is introduced into the furnace chamber 14 as shown in Figure 3. The in-furnace thermocouple 4, firing table 8, and stage 9 are positioned so that the tip of the in-furnace thermocouple 4 does not collide with the prosthesis 7 or the firing table 8. In the present invention, a positioning pin 5 is set in the stage 9, and the firing table 8 is placed on the stage 9 by fitting the positioning hole into the positioning pin 5. The positioning means is not limited to these, and any heat-resistant pin, guide, hole processing, etc. can be used. The firing table 8 is made of a heat-insulating material that can withstand high temperatures, such as alumina fiber or ceramic fiber.

[0015] A motor, pneumatic cylinder, hydraulic cylinder, etc. can be used as the drive source for the lifting device 12, but a motor, which has excellent position and speed controllability, is particularly preferable. The lifting device 12 may be equipped with a collision detection means that detects the load on the motor during lifting operation and stops the lifting operation if the load exceeds a predetermined level. The collision detection means can prevent damage to the firing table 8, furnace thermocouple 4, prosthesis 7, etc.

[0016] Furthermore, an in-chamber thermocouple 30 is provided at a position below the stage 9 (within the projection plane of the stage 9 projected onto the floor) when the stage 9 is positioned at the lowest position by the lifting device 12. Details will be described later in the description of the third embodiment.

[0017] 4 shows a control block diagram of the dental baking device 13 according to the present invention. An operation unit 101 is provided on the front side of the dental baking device 13, and baking instructions including baking conditions and instructions to start baking are input to the control unit 100 via this operation unit 101. Note that, although this embodiment describes a configuration in which baking instructions are input from the operation unit 101, the present invention is not limited to this, and baking instructions may also be input from an external information processing device or the like.

[0018] The control unit 100 controls the operation of the heater 1, the lifting device 12, and the actuator 19 as described above based on the firing command to fire the prosthesis 7. The system also has fans 21 and 22 for circulating air between the work area 26 and the outside of the housing, particularly while the stage 9 is being lowered after the firing operation is completed. In this embodiment, as an example, the fan 21 is provided on the left side of the work area 26, and the fan 22 is provided on the right side of the work area 26. Each fan is arranged to blow air into the work area 26, but this is not a limitation and may be selected as appropriate.

[0019] (Unlock by monitoring the temperature of the thermocouple inside the furnace) The opening and closing control of the door 17 in the present invention will be described below. The control of each process is executed by the control unit 100 shown in Fig. 4 issuing instructions to each unit. After being energized (powered on), the dental baking device 13 operates according to the flowchart shown in Fig. 5.

[0020] In step S1, when power is applied to the dental baking device 13, the control unit 100, which functions as a lock control unit, issues a command to unlock the electromagnetic lock 20, and in step S2, the actuator 19 is driven to unlock the door 17, making it possible to open the door.

[0021] In step S3, the user places the prosthesis 7 on the firing table 8. Before heating, the temperature of the work area 26 is low.

[0022] In step S4, when the door 17 is closed, the actuator 19 on the door side is inserted into the electromagnetic lock 20, and the door 17 is put into a locked state.

[0023] In step S5, the user selects a baking condition program from pre-registered programs via the operation unit 101, or sets the program by inputting the program from the operation unit 101, and in step S6, it is determined that the door 17 is locked (YES in S6), and the set program is started.

[0024] At this time, the program is set not to start if the door 17 is unlocked. If the door 17 is locked, the program starts and proceeds to step S7, the stage 9 rises, the prosthesis 7 and the firing table 8 are introduced into the furnace chamber 14, and power is turned on to the heater 1. The temperature is raised to the target temperature according to the program set in step S8, and after the target temperature is reached, firing (holding) is carried out at that temperature for a predetermined time.

[0025] When the set baking time has elapsed, it is determined that baking of the prosthesis 7 has been completed, and in step S9 the stage 9 is lowered, and in step S10 cooling is started by the fans 21 and 22 (not shown).

[0026] In step 11, when it is detected that the temperature of the furnace thermocouple 4 installed in the furnace chamber 14 has fallen below a predetermined temperature, for example, 800°C, it is determined in step 12 that the program has been completed, and in step 13, electricity is applied to the electromagnetic lock 20 to unlock the door 17.

[0027] If the temperature of the furnace chamber 14 is 800°C or higher, the process returns to step 10 and cooling is continued until the temperature is below 800°C.

[0028] In step S14, the door 17 is opened, and the stage 9 cooled in step S15 and the prosthesis 7 can be removed from the work area 26.

[0029] <Example 2> (Unlock after cooling time) A dental baking apparatus according to a second embodiment of the present invention will be described below. The dental baking apparatus according to this embodiment has many of the same components as those of the first embodiment, and the same reference numerals are used for those components, and the description thereof will be omitted. After being energized, the dental baking apparatus 13 operates according to the flowchart shown in FIG.

[0030] The process is the same as in the first embodiment up to step S10, in which the baking of the prosthesis 7 is completed (after the heating is completed), the stage is lowered, and cooling is performed by the air blower.

[0031] In step 11, the control unit 100, which functions as a time measurement means, measures the elapsed time of the program for firing the prosthesis 7, and when it detects that a predetermined time, for example, 10 minutes, has elapsed since the start of cooling, it determines in step 12 that the program has been completed, and in step 13, the electromagnetic lock 20 is energized to unlock the door 17. If the cooling time has not elapsed for 10 minutes, the process returns to step 10 and cooling continues until 10 minutes have elapsed.

[0032] In step S14, the door 17 is opened, and the stage 9 cooled in step S15 and the prosthesis 7 can be removed from the work area 26.

[0033] The specified time for unlocking the door 17 depends on the firing temperature profile of the prosthesis 7 to be fired, but it is preferable to measure the specified time for the temperature of the furnace chamber 14 to drop in advance and set the specified time based on the results.

[0034] <Example 3> (Unlocking by monitoring the temperature with a thermocouple inside the cabinet) After being energized, the dental baking apparatus 13 operates according to the flowchart shown in FIG.

[0035] The process is the same as in the first embodiment up to step S10, in which the baking of the prosthesis 7 is completed, the stage is lowered, and cooling is performed by the air blower.

[0036] In this embodiment, as shown in Fig. 8, an in-cabinet thermocouple 30, which is a door temperature detection means, is provided between the stage 9 and the floor of the work area 26, and is configured to indirectly measure the temperatures of the stage and the baking table 8, which become hot due to temperature rise and mooring, in the work area when the baking of the prosthesis 7 is completed and the stage is lowered. Although a thermocouple is used, a thermistor may also be used as long as it can measure the temperature.

[0037] The internal thermocouple 30 measures the temperature in the vicinity of the stage 9 without contacting the stage 9. Furthermore, it is desirable that the internal thermocouple 30 be placed within the projection plane of the stage 9 projected onto the floor surface.

[0038] By placing the internal thermocouple 30 within the projection plane of the stage 9, the wind from the fan cooling the prosthesis 7 hits the prosthesis 7 or the baking table 8 on the stage, but does not hit the internal thermocouple 30 directly, preventing a sudden drop in the detected temperature alone, and making it possible to measure the temperature near the back surface of the stage.

[0039] In step 9, when the firing of the prosthesis 7 is completed (heating is completed) and the stage 9 is lowered, the firing table 8 and stage 9 that have been heated together with the prosthesis due to the temperature increase and anchoring are lowered, and the temperature of the work area 26 increases.

[0040] When cooling is started by the blower in step 10, the temperatures of the work area 26, the prosthesis 7, the baking table 8, and the stage 9 gradually decrease.

[0041] In step 11, when it is detected that the temperature of the internal thermocouple 30 installed on the floor surface has fallen below a predetermined temperature, for example, 60°C, it is determined in step 12 that the program has been completed, and in step 13, electricity is applied to the electromagnetic lock 20 to unlock the door 17.

[0042] If the temperature of the internal thermocouple 30 is 60°C or higher, the process returns to step 10 and cooling is continued until the temperature drops below 60°C.

[0043] In step S14, the door 17 is opened, and the stage 9 cooled in step S15 and the prosthesis 7 can be removed from the work area 26.

[0044] <Example 4> (Unlock by monitoring temperature with an optical sensor) After being energized, the dental baking apparatus 13 operates according to the flowchart shown in FIG.

[0045] The process is the same as in the first embodiment up to step S10, in which the baking of the prosthesis 7 is completed, the stage is lowered, and cooling is performed by the air blower.

[0046] In this embodiment, an optical sensor, for example, an infrared sensor, is used to measure the temperature of the prosthesis 7. As shown in Figure 10, the optical sensor 31 is installed near the blower, for example, where it is less susceptible to the temperature from inside the furnace after the stage is lowered. Furthermore, a heat shield member 25 may be installed between the furnace chamber 14 and the optical sensor 31.

[0047] In step 11, when the optical sensor 31 installed in the work area 26 detects that the temperature of the prosthesis 7 measured has fallen below a predetermined temperature, for example, 60°C, the program is determined to be complete in step 12, and in step 13, the electromagnetic lock 20 is energized to unlock the door 17.

[0048] If the temperature of the prosthesis 7 is 60°C or higher, the process returns to step 10 and cooling is continued until the temperature falls below 60°C.

[0049] In step S14, the door 17 is opened, and the stage 9 cooled in step S15 and the prosthesis 7 can be removed from the work area 26.

[0050] Next, in Examples 1 to 4, the opening and closing control of door 17 when power to dental baking apparatus 13 is cut off due to a power outage or the like will be described.

[0051] When power is normally supplied, the dental baking device 13 operates in accordance with the flowcharts described in the respective embodiments.

[0052] When the power is cut off and when the power is restarted, the operation follows the flowchart shown in FIG.

[0053] When the power supply to the dental baking apparatus 13 is cut off, the program stops in step S21 and the operation stops.

[0054] In step S22, the electromagnetic lock 20 has a mechanical lock structure that uses the force of a spring to maintain the locked state (closed state) even when power is not applied. This prevents the door 17 from being opened and allows safety to be ensured even if power is cut off when the work area 26 is at a high temperature, such as while the heater 1 is heating up or while the stage 9 is lowering after firing.

[0055] The operation when power is restored will be described below.

[0056] When the power supply to dental baking apparatus 13 is resumed, in step S24, the control that was in place before the power cut is stopped, stage 9 is lowered, and in step S25, cooling by the blower is started.

[0057] In step S26, measurement is started using the in-furnace thermocouple 4 installed in the furnace chamber 14. When it is detected that the temperature of the in-furnace thermocouple 4 has fallen below a predetermined temperature, for example, 800°C, it is determined that the temperature of the work area 26 has dropped, and in step 27, the electromagnetic lock 20 is energized to unlock the door. If the temperature is 800°C or higher, it is determined that the work area 26 is too hot, and the process returns to step S25, where cooling is continued until the temperature falls below 800°C.

[0058] In step S28, the door 17 is opened, and in step S29, the prosthesis 7 can be removed from the cooled stage area.

[0059] The door 17 may also be opened at a stepped angle. When the firing of the prosthesis 7 is completed and the stage is lowered, while the internal thermocouple 30 detects that the temperature in the work area is above a predetermined temperature, for example, 60°C, the electromagnetic lock 20 is energized to unlock the door 17, causing the door to open automatically one step, allowing hot air to escape and shortening the cooling time of the prosthesis 7. When it is detected that the temperature has dropped to around 60°C, the door is unlocked another step. When it is detected that the temperature is below 60°C, the door is completely unlocked and the door 17 is opened, visually informing the user that the prosthesis 7 can be removed. This configuration may also be configured so that the door 17 is opened manually.

[0060] In addition, when the actuator 19 is inserted into the electromagnetic lock 20, there may be a gap between the electromagnetic lock 20 and the actuator 19, so that the door can open to a position that is slightly tilted forward from the vertical even when the door is locked by the electromagnetic lock.

[0061] When firing the prosthesis 7, the door 17 is closed and locked by the electromagnetic lock 20. In the locked state, the door 17 is tilted toward the front from the vertical direction, so that the door 17 will not open under its own weight.

[0062] When the firing of the prosthesis 7 is completed and the stage 9 is lowered, the door can be slightly opened even in the locked state.

[0063] At this time, the gap between the door 17 and the main body is only small on the left and right sides and in the upper direction of the device main body, and the warm air in the work area 26 can be released to the outside without affecting the worker in front of the main body.

[0064] In this way, the heated air in the working area 26 can be discharged outside the dental baking device 13 without being exposed to high temperatures, while ensuring safety, thereby shortening the cooling time in the working area 26.

[0065] In this embodiment, the door 17 is configured to be opened manually, but a motor and gear may be attached to the hinge so that the door opens automatically after cooling is completed.

[0066] The present invention is not limited to the above-described embodiments, and various modifications can be applied within the scope of the present invention. [Explanation of symbols]

[0067] 1 heater 2 Side insulation 3 Top insulation 4 Furnace thermocouple 5 Locating Pins 7. Prosthetics 8 baking table 9 Stages 11 Electric wire 12 Lifting device 13 Dental baking equipment 14 Furnace room 17 Doors 19 Actuators 20 Electromagnetic Lock 21 Blower 22 Blower 24 Louvers 25 Heat shielding material 26 Work Area 30 Internal thermocouple 31 Optical Sensor 100 control section 101 Operation section

Claims

1. a heating means for heating the object to be fired in the furnace; a furnace thermocouple for measuring the temperature inside the furnace; A hearth on which the object to be fired is placed; a drive means for moving the hearth from the furnace downwardly to a work area; a door covering the work area; a locking mechanism provided in the housing for locking the door; a lock control unit that controls the lock mechanism; and After the heating of the object to be fired is completed, the drive means lowers the hearth from the furnace to the work area, and when the object to be fired has cooled to a predetermined temperature, the lock control unit releases the lock mechanism.

2. The baking device according to claim 1, characterized in that, after the heating of the baking object is completed, the lock control unit releases the lock mechanism when it is detected using the in-furnace thermocouple that the baking object has dropped to the predetermined temperature.

3. A time measuring means for measuring time is provided, The baking device according to claim 1, characterized in that the lock control unit releases the lock mechanism when the timing means detects that a predetermined time has elapsed since the heating of the baking object was completed and that the baking object has dropped to the predetermined temperature.

4. a door temperature detection means for detecting a temperature inside the door, the door temperature detection means being provided within a projection plane of the hearth projected onto the floor surface of the work area; The baking device according to claim 1, characterized in that after the baking object has been heated, the lock control unit releases the lock mechanism when the door temperature detection means detects that the baking object has dropped to the predetermined temperature.

5. 5. The baking apparatus according to claim 4, further comprising a blower for blowing air toward the hearth in the work area.

6. An optical sensor for measuring the temperature of the baking object is provided, 2. The baking device according to claim 1, wherein the lock control unit releases the lock mechanism when the optical sensor detects that the temperature of the baking object has dropped to the predetermined temperature after the baking object has been heated.

7. When the power supply to the device is cut off, the door is kept closed by the locking mechanism, The baking device according to any one of claims 1 to 6, characterized in that the lock control unit releases the lock mechanism when the temperature of the baking object drops to the predetermined temperature when power is supplied to the device.

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