JPH1140332A - Ceramic art furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the safety property of a ceramic art furnace. SOLUTION: A microcomputer 46 receives the information of a temperature inside a furnace sensed by a thermocouple 14 through a temperature sensing circuit 51 and judges whether the door of the furnace chamber is open or not by means of a sensing signal from a door switch 52 when the temperature in the furnace is within a range of 100 to 800 deg.C. If the door is open, it actuates an alarm circuit 49 in order to generate an alarm sound. When the temperature in the furnace is above 800 deg.C, it sends a control signal to a solenoid-driving circuit 53 so as to lock the door into a locked state and consequently, the door can not be opened even if a user pushes a release switch. Thus, an operator is kept from opening the door carelessly and touching a hot heating body during a heating operation or prevented from being exposed to an extremely hot heat wind from the furnace.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a pottery furnace for firing pottery.

[0002]

2. Description of the Related Art As a pottery furnace for firing relatively small pottery, an electric furnace is widely used because it is relatively easy to handle. In this type of conventional pottery furnace, a heating wire such as a nichrome wire or a kanthal wire is provided on the inner peripheral wall of the furnace chamber made of heat insulating material. It has a relatively simple configuration in which heating is performed by energizing a wire (see, for example,
-171083, JP-A-61-171084, etc.).

[0003]

In general, the pottery furnace requires a great deal of care in handling since the temperature in the furnace chamber is as high as 1000 ° C. or higher. Conventional pottery furnaces of this type have been used in relatively specialized places such as, for example, industrial test sites. For this reason, users are mainly workers who are accustomed to handling, and work is performed according to predetermined procedures. However, in recent years, pottery has been widely spread as a hobby, and, for example, opportunities for relatively unfamiliar people to use pottery furnaces installed in pottery classes and public facilities (for example, public halls) in each region are increasing. For this reason, the work may not be performed according to a predetermined work manual, or the work may be performed without consideration for safety.

[0004] In view of the above, there is a demand for a pottery furnace which is considered more safety than the conventional one. The present invention has been made in view of such problems, and an object of the present invention is to provide a pottery furnace with improved handling safety.

[0005]

Means for Solving the Problems, Embodiments of the Invention, and Effects of the Invention The present invention, which has been made to solve the above-mentioned problems, comprises a substantially sealed furnace chamber having a door, A pottery furnace comprising heating means for firing the housed pottery, a) detecting means for detecting the open / closed state of the door, b) temperature measuring means for measuring the temperature inside the furnace chamber, c ) Notification means for notifying an abnormality; d) when the temperature measured by the temperature measurement means is equal to or higher than a first predetermined temperature, the notification means is driven when the detection means detects the opening of the door body. And control means for performing the operation.

In the pottery furnace of the present invention, when heating is started, the control means determines whether or not the temperature in the furnace chamber measured by the temperature measuring means has reached a first predetermined temperature. If the temperature is equal to or higher than the predetermined temperature, it is determined by the detection means whether or not the door is open. For example, when the door is opened by the user during heating, the control unit recognizes this and drives the notification unit. As the notification means, for example, a sound generation means such as a buzzer or a display means can be used.
The user can be alerted by such notification, and the danger of the user touching the furnace chamber, which is hot, can be prevented.

Further, the furnace temperature is extremely high (for example, 10
(Close to 00 ° C), even the hot air flowing out of the furnace chamber when the door is opened requires attention. Therefore, the pottery furnace of the present invention further includes a locking unit that prohibits the opening of the door body, and the control unit includes a second unit whose temperature measured by the temperature measuring unit is higher than a first predetermined temperature. When the temperature is equal to or higher than a predetermined temperature, the door may be locked by the locking means. Usually, the second predetermined temperature is set to a temperature much higher than the first predetermined temperature.

According to such a configuration, when the furnace temperature is extremely high, the door is not opened even if a normal operation for opening the door is performed, and the safety is further improved.

[0009] Further, even when the temperature in the furnace chamber is high, the user may want to open the door intentionally. Therefore, in the ceramic art furnace of the present invention, the locking by the locking means can be released by a predetermined operation. It is preferable to have a configuration. As the release means, for example, a switch disposed at a position where it is difficult to operate (for example, a side surface of the housing) or hidden by a lid can be used. According to such a configuration, it is possible to prevent the door from being opened by a careless operation of the user when the furnace chamber is extremely hot, and it is necessary to intentionally open the door when it is desired to open the door. Can be opened accordingly.

[0010] In the pottery furnace of the present invention, the furnace chamber is formed of a heat insulator, and the heating means includes a tubular metal body inserted into the furnace chamber and capable of housing the pottery therein; And a power supply means for supplying high-frequency power to the coil and inductively heating the metal body with the coil wound around the outer periphery of the metal body.

That is, when the power supply means supplies high-frequency power to the coil, an alternating magnetic flux is generated in the coil, which penetrates both ends of the metal body and passes through the inside of the metal body. An AC current is mainly induced in the metal body in the circumferential direction by the magnetic flux, and the metal body is heated by resistance loss. Since the metal body is covered with a heat insulator, the generated heat is concentrated on the inner peripheral side of the metal body, and its temperature becomes extremely high. Thereby, the pottery housed therein is fired.

[0012] In the conventional heating using the heating wire, the wire itself is heated to a high temperature and is likely to be oxidized and the wire is easily broken. Reliability can be improved.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the ceramic potter according to the present invention will be described below with reference to the drawings. 1 is a perspective view showing the appearance of the pottery furnace of the present embodiment, FIG. 2 is a perspective view showing a state in which a front door of the pottery furnace is opened, FIG. 3 is a partial sectional perspective view showing the structure of a furnace chamber, FIG. 4 is a partial cross-sectional side perspective view showing a configuration of a main part in a housing centering on the furnace chamber, and FIG. 5 is a cross-sectional front perspective view showing a configuration of a main part in the housing also centering on the furnace chamber. 6 is a front plan view (a) and a side plan view (b) showing the appearance of the heating element, FIG. 7 is a plan view of the operation panel, and FIG. 8 is a top perspective view (a) and a part of the vicinity of the door and the operation panel. FIG. 9 is a right side perspective view of the same portion as FIG.

As shown in FIG. 1, a door 3 and an operation panel 6 are provided on the front side of a casing 2 of the pottery furnace 1 according to the present embodiment. As shown in FIG. 7, the operation panel 6 includes a display panel 61 for mainly displaying the furnace temperature, and various key input switches for selecting a course in which a heating pattern is determined in advance, for instructing a heating start, and the like. 62, a main power switch 63, and a release switch 64 for opening the door 3 are provided. A handle 4 protruding in a columnar shape is provided on the front surface of the door 3, and an intake hole 5 also serving as a peep hole is formed in the center of the door 3. As shown in FIG. 2, when the door 3 is opened, the furnace chamber 10 is opened at substantially the center, and substantially the entire surface is closed except for the opening.

As shown in FIG. 3, the furnace chamber 10 has five furnace walls 11, excluding the front opening, formed of a heat insulating material, and the inside thereof is hollow in the shape of a quadrangular prism. A cylindrical heating element 12 having a substantially square cross section is fitted in the space inside the furnace chamber 10 so as to be able to be pulled out forward. The heat insulating material constituting the furnace wall 11 has a three-layer structure including a first heat insulating layer 11a, a second heat insulating layer 11b, and a third heat insulating layer 11c, as described later in detail. The coil 13 is wound around
The outside of the coil 13 is surrounded by a third heat insulating layer 11c. The coil 13 is connected to a high-frequency power supply including an inverter circuit described later.

During heating, the temperature inside the furnace chamber 10 is 1000-
Since the temperature reaches as high as 1300 ° C., the heat insulating material constituting the furnace wall 11 is required to have high heat resistance. Further, in order to make the furnace wall 11 as thin as possible, high heat insulation performance is also required. For this reason, a heat insulating material having both heat resistance and heat insulating properties is preferable, but in practice, it is difficult to obtain such a material. Therefore, in the pottery furnace 1 of the present embodiment, a furnace wall 11 having necessary performance is formed by laminating a plurality of heat insulating materials having different characteristics.

That is, heat resistance is emphasized particularly on the inner peripheral side of the furnace wall 11 where the temperature is high, and heat insulation is emphasized on the outer peripheral side where the temperature is lowered to some extent. Specifically, for example, the first heat insulating layer 11a is a ceramic molded material having a thickness of 12.5 mm, the second heat insulating layer 11b is a silica-based heat insulating material having a thickness of 10 mm, and the third heat insulating layer 11c is a calcium silicate having a thickness of 13 mm. It is used as a thermal insulation material. The ceramic molding material used as the first heat insulating layer 11a has a very high heat resistance temperature of about 1400 ° C., but has relatively low heat insulating performance. The calcium silicate-based heat insulating material used as the third heat insulating layer 11c has a heat resistance temperature of about 800 ° C., and similarly has relatively low heat insulating performance. Since both are heat insulating materials having high robustness, their surfaces are exposed and are suitable for the first heat insulating layer 11a and the third heat insulating layer 11c which form the furnace chamber 10.

On the other hand, the silica-based heat-insulating material used as the second heat-insulating layer 11b has a heat-resistant temperature of about 800 ° C. and has high heat-insulating performance, but has a brittle surface. Therefore, in order to enable the coil 13 to be wound around the second heat insulating layer 11b and to protect the surface thereof, a mica plate 11d is disposed between the outer periphery of the second heat insulating layer 11b and the coil 13. doing. The mica plate 11d has a thickness of 0.5 mm and a heat resistant temperature of about 600 ° C.

As shown in FIGS. 4 and 5, the furnace chamber 10 includes:
The support frame 7 made of metal is firmly supported at a predetermined position inside the housing 2. On the back side of the door 3, a convex heat insulating material 3 a that is strongly adhered to the furnace wall 11 at the front end of the furnace chamber 10 when the door 3 is closed is adhered. Sealed. Further, a thermocouple 14 for measuring the temperature inside the furnace chamber 10 penetrates the rear wall surface of the furnace chamber 10. Further, an exhaust hole 15 is provided in the wall surface thereafter, and the inside of the furnace chamber 10 and the space in the housing 2 behind the furnace chamber 10 communicate with each other via an L-shaped exhaust pipe 16. Gas exhausted from the inside of the furnace chamber 10 through the exhaust pipe 16 is supplied to the gas guide plate 8 covering the upper part of the space behind the furnace chamber 10.
, And is discharged to the outside of the housing 2 through the ventilation port 2a at the top rear of the housing 2.

The heating element 12 inserted into the furnace chamber 10 includes:
For example, as shown in FIG. 6, the folded portion 12a is formed of a metal plate such as stainless steel, and has three edges other than the lower edge of the opening at both ends, the edges of which are folded inward and which are in close contact with the outer plate surface.
Has formed. The lower edge is folded inward at a predetermined distance from the outer plate surface to form a support base piece 12b. A notch is formed on each side surface at a position substantially equidistant from the opening surfaces at both ends, and the support protrusion 12d is formed by being bent substantially horizontally inside. At this time, the support projection 12d and the support base piece 12b are at substantially the same height, and the mounting plate 17 for mounting the ceramic on the upper surface is inserted from the front, and the support projection 12d and the support projection 12d are supported. It can be held horizontally by the base piece 12b.

Next, an opening mechanism of the door 3 of the pottery furnace 1 according to the present embodiment will be described with reference to FIGS. On the rear surface of the release switch 64 disposed below the operation panel 6, there is provided an extruding member 21 having an upper surface formed obliquely.
The pushing member 21 is urged forward by a spring 22.
Due to the contraction force of the spring 22, the switch 6 depressed
4 returns to the original position immediately when the pushing force is released. When the switch 64 is pushed, the pushing member 21 is pushed.
Pushes up the operating rod 24 via the roller 23.
The operating rod 24 is pushed up substantially vertically along the guide cylinder 25, and when the switch 64 returns to its original position, the operating rod 24
Is also lowered by the contraction force of the spring 26. The pushed end 24a of the operating rod 24 pushes the lower end of a door lever 3b rotatably provided on the back surface of the door 3. Then, the door lever 3b rotates upward, the engagement between the pin 27 formed on the housing 2 side and the door lever 3b is released, and the door 3 can be opened.

Further, a locking member 29 that rotates about a shaft 28 is provided at the back of the pushing member 21.
A solenoid 30 having a plunger 30a protruding forward is provided on the rear surface of the lower end of 9. Solenoid 30
Is driven to project the plunger 30a, the locking member 29 rotates upward about the shaft 28 and blocks the space behind the pushing member 21. As a result, the switch 64 cannot be depressed, and the door 3 is locked in the closed state.

When using the pottery furnace 1 of the present embodiment having the above-described configuration, the user opens the door 3 and places the pottery on the placement plate 17 inside the furnace chamber 10. . And
The door 3 is closed, the furnace chamber 10 is sealed, and a predetermined operation is performed on the operation panel 6 to instruct heating. When a high-frequency current is supplied to the coil 13 from a high-frequency power supply having a circuit as described later, a magnetic flux passes through the opening surfaces at both ends of the heating element 12, and an induced current flows in a circumferential direction of the heating element 12 by the magnetic flux. When this induced current flows through the heating element 12, Joule heat is generated, and the heating element 12 itself is heated. Of course, a part of the magnetic flux circulating in the vicinity of each turn of the coil 13 penetrates the heating element 12 vertically or obliquely, thereby locally generating an eddy current. The thing by current is dominant. Since the heating element 12 is surrounded by a heat insulating material, heat is concentrated inside the heating element 12 and its temperature is 1000 to 130.
It reaches 0 ° C. Thereby, the pottery housed inside the heating element 12 is fired.

In the ceramic furnace having such a configuration, the coil 13
As the distance between the heating element 12 and the heating element 12 increases, the magnetic flux passing through the inside of the heating element 12 decreases, so that the heating efficiency deteriorates. For this reason,
As long as the heat resistance of the coil 13 permits, the heating element 1
It is preferable to approach 2. Therefore, in the pottery furnace of the present embodiment, as described above, the second heat insulating layer 11b and the third heat insulating layer 1
By arranging the coil 13 in the gap with the coil 1c, it is possible to prevent the temperature of the coil 13 itself from becoming high without sacrificing much the heating efficiency.

FIG. 10 shows an example of an electric system configuration in the pottery furnace of this embodiment. The 100 V commercial power supply 40 is connected to the rectifier circuit 41 via a main power switch 63 for mechanically turning ON / OFF. On the front side (AC side) of the rectifier circuit 41, an input detection circuit 42, and a motor 43 and a motor drive circuit 44 for driving a fan for forcibly exhausting the inside of the housing 2 are provided. The output of the rectifier circuit 41 is output from the output control circuit 45a and the transistor drive circuit 4
5b, and supplies a predetermined high-frequency current to the coil 13. A microcomputer with a CPU at the center of control (microcomputer)
A display panel 61 is provided in addition to the input detection circuit 42, the motor drive circuit 44, and the output control circuit 45a.
, A key input circuit 48 and an alarm circuit 49, a reset circuit 50, a temperature detection circuit 51, and a door switch 5 attached to the key input switches 62.
2. The drive circuit 53 of the solenoid 30 and the oscillation circuit 54 are connected.

The control during the heating operation, which is a feature of the pottery furnace of the present invention, will be described below with reference to the flowcharts of FIGS.

When the main power switch 63 is turned on (step S1), a power supply current is supplied to the microcomputer 46 to enter a standby mode (step S2). First, microcomputer 4
6 executes an initialization process (step S3), and thereafter receives information on the furnace temperature T detected by the thermocouple 14 from the temperature detection circuit 51 (step S4). Next, it is determined whether or not the course selection key has been pressed based on a signal from the key input circuit 48 (step S5). If the course selection key has not been pressed, the process returns to step S4 to execute the furnace temperature detection processing again. I do. If it is determined in step S5 that the course selection key has been pressed, the information on the furnace temperature T detected in step S4 is sent to the display circuit 47, and the display panel 6
In step S6, a temperature monitor is displayed.

Next, the microcomputer 46 has a key input circuit 48.
It is determined whether or not the start key has been pressed based on the signal from (step S7). If the start key has been pressed, the process proceeds to the following process. That is, the furnace temperature T is received from the temperature detection circuit 51 (step S8), and based on this, a predetermined control signal is sent to the output control circuit 45a to operate the inverter circuit 45 (step S9). This allows
A predetermined high-frequency current flows through the coil 13 and heats the heating element 12 as described above. Then, information on the furnace temperature T detected earlier in step S7 is sent to the display circuit 47, and the temperature monitor display on the display panel 61 is updated (step S1).
0).

Thereafter, it is determined whether or not the operation of the selected course has been completed (step S11). If the operation has not been completed, the process returns to step S4 to repeat the processing of steps S4 to S7. The operation is terminated, for example, after the furnace temperature T reaches the maximum temperature preset according to the selected course, and after that, the temperature is kept at that maximum temperature for about 10 to 60 minutes. You. When the operation is completed, the heating output control processing in step S9 is not performed (that is, heating is stopped), the furnace temperature T detection processing (step S12) and the temperature monitor display processing (step S1).
Repeat only 3). Thus, the furnace temperature T
Gradually descends after reaching the maximum temperature. The user can determine the timing for removing the pottery housed in the furnace chamber 10 while watching the temperature display.

In the above series of processes, after the start key is pressed, an interrupt process A shown in the flowchart of FIG. 12 and an interrupt process B shown in the flowchart of FIG. 13 are executed at appropriate intervals. That is, in the interrupt processing A, the microcomputer 46 determines whether or not the cancel key is pressed based on a signal from the key input circuit 48 (step S21). If the cancel key is pressed, heating is stopped even during heating. To return to standby mode and wait.

In the interrupt processing B, first, the microcomputer 4
6 determines whether the detected furnace temperature T is equal to or higher than a predetermined temperature T1 (step S31). For example, T1 is set to about 100 ° C. If it is determined that the furnace temperature T is equal to or higher than T1, the furnace temperature T is then increased to a predetermined temperature T1.
It is determined whether it is 2 or more (step S32). T2
Is set to a temperature much higher than T1, for example, set to about 800 ° C. When the furnace temperature T is lower than T2,
It is determined whether or not the door 3 is open based on the detection signal of the door switch 52 (step S34). If it is determined that the door 3 is open, the microcomputer 46 sends a drive signal to the alarm circuit 49 to sound an alarm (step S35).

In step S32, the furnace temperature T is set to T2.
If it is determined that the above is the case, the microcomputer 46 sends a drive signal to the solenoid drive circuit 53. Accordingly, the plunger 30a protrudes forward as described above, and the locking member 29 restricts the movement of the pushing member 21. Therefore, the user cannot depress the release switch 64, and the opening of the door 3 is prohibited (step S33). This door lock is performed when the furnace temperature T falls below T2, when a lock release switch (not shown) is pressed by the user, or when the main power switch 63 is once shut off and turned on again to execute initialization processing. (If the furnace temperature T is equal to or higher than T2), the release switch 64 is depressed and the release switch 64 can be pushed.

If it is determined in step S31 that the furnace temperature T is lower than T1, or if it is determined in step S34 that the door 3 is closed, if the alarm is sounding, the alarm is sounded. It stops (step S36). For this reason, once the alarm starts to sound, the alarm continues to sound until the furnace temperature T falls to T1 or lower or the door 3 is closed. This prevents the user from inadvertently opening the door 3.

The above embodiment is merely an example, and it is apparent that changes and modifications can be made within the spirit of the present invention.

[Brief description of the drawings]

FIG. 1 is a perspective view showing the appearance of a ceramic pot according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a state where a front door of the pottery furnace of FIG. 1 is opened.

FIG. 3 is a perspective view, partly in section, showing a structure of a furnace chamber of the pottery furnace of the present embodiment.

FIG. 4 is a partially sectional side perspective view showing a configuration of a main part in a housing centering on a furnace chamber of the pottery furnace of the present embodiment.

FIG. 5 is a partial cross-sectional front perspective view showing a configuration of a main part in a housing centering on a furnace chamber of the pottery furnace of the present embodiment.

FIG. 6 is a front plan view (a) and a side plan view (b) showing the appearance of the heating element of the pottery furnace of the present embodiment.

FIG. 7 is a plan view of an operation panel of the pottery furnace according to the present embodiment.

FIG. 8 is a top perspective view (a) and a partial front view (b) of the vicinity of the door and the operation panel of the pottery furnace of the present embodiment.

FIG. 9 is a right side perspective view of the same place as in FIG. 8;

FIG. 10 is an electrical configuration diagram of the pottery furnace of the present embodiment.

FIG. 11 is a control flowchart at the time of a heating operation of the pottery furnace of the present embodiment.

FIG. 12 is a control flowchart at the time of a heating operation of the pottery furnace of the present embodiment.

FIG. 13 is a control flowchart at the time of a heating operation of the pottery furnace of the present embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 3 ... Door 3b ... Door lever 4 ... Handle 6 ... Operation panel 62 ... Key input switches 64 ... Release switch 10 ... Furnace chamber 11 ... Furnace wall 12 ... Heating element 13 ... Coil 14 ... Thermocouple 21 ... Extruded members 22, 26 ... Spring 23 ... Roller 24 ... Operation rod 25 ... Guide cylinder 27 ... Pin 28 ... Shaft 29 ... Locking member 30 ... Solenoid 30a ... Plunger 45 ... Inverter circuit 46 ... Microcomputer 48 ... Key input circuit 49 ... Alarm circuit 51 ... Temperature detection circuit 52: Door switch 53: Solenoid drive circuit

Claims (4)

[Claims] 1. A pottery furnace comprising: a substantially closed furnace chamber having a door body; and heating means for firing pottery housed in the furnace chamber, a) opening and closing the door body. Detecting means for detecting; b) temperature measuring means for measuring the temperature inside the furnace chamber; c) notifying means for notifying an abnormality; d) the temperature measured by the temperature measuring means is a first predetermined value. A pottery furnace, comprising: a control unit that drives the notification unit when the opening of the door is detected by the detection unit when the temperature is equal to or higher than the temperature. 2. The vehicle according to claim 1, further comprising a locking unit that prohibits the opening of the door body, wherein the control unit determines that the temperature measured by the temperature measuring unit is equal to or higher than a second predetermined temperature higher than the first predetermined temperature. 2. The pottery furnace according to claim 1, wherein the door is locked by the locking means. 3. The pottery furnace according to claim 2, wherein the locking by the locking means can be released by a predetermined operation. 4. The furnace chamber is formed of a heat insulator, and the heating means is formed of a cylindrical metal body inserted into the furnace chamber and capable of housing ceramics therein. The pottery furnace according to any one of claims 1 to 3, comprising: a coil wound around the outer periphery; and power supply means for supplying high-frequency power to the coil and inductively heating the metal body.