JP3369988B2 - Bunsen gas pottery kiln - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention enables oxidation and reduction firing in a Bunsen type gas pottery kiln, which requires secondary air for combustion used for firing ceramics, even without a chimney which was conventionally required. , And enabled automatic control
Bunsen gas pottery kiln.

[0002]

2. Description of the Related Art Conventionally, the structure of a pottery kiln A'is shown in FIG.
As shown in FIG. 7 and FIG. 7, a burner block 102 is provided at the crater of the hearth 101 of the furnace, and the Bunsen gas burner 1
03 is attached to the lower part of the furnace facing the burner block 102, the flame is once raised to the ceiling, and then the draw hole 10 in the hearth
4, the chimney 10 through the horizontal flue 105 and the vertical flue 106
The method called the falling flame method that discharges from 7 is common,
And it was practical. In the case of the inversion flame type, since the chimney is raised, the chimney 107 is provided so as to project to the outside from the roof 112 or the like. The chimney 107 affects the performance of the furnace and may not be too short or too long. Chimney 1 for pottery kiln A '
Reference numeral 07 denotes not only a hole for discharging combustion exhaust gas in the furnace but also a damper 11 provided at the lower opening 108 of the chimney.
By changing the draft pressure caused by the presence of a long chimney by arbitrarily operating the opening degree of 0, the amount of air sucked from the secondary air holes can be adjusted arbitrarily to change the combustion state in the furnace to air. As it is an important factor that can be freely changed to reducing combustion with (oxygen) deficiency and oxidative combustion with excess air (oxygen), the Bunsen burner does not have a long chimney.
There was no pottery kiln that could be used.

In the conventional Bunsen gas pottery kiln A'having a long chimney, the vertical flue 1 at the bottom of the chimney is shown in FIG.
The damper 11 for adjusting the draft pressure is provided in the lower opening 108 of the 06.
0 is provided so that it can be manually moved to the left and right and opened and closed to adjust the opening degree. By adjusting the opening and closing of the damper, reduction in the furnace,
It is provided to control oxidative combustion. The damper is provided with a hooking hole 111 which is opened and closed by a jig or the like. When this damper 110 is opened, the chimney draws in outside air from the damper part, so secondary air does not enter the kiln, resulting in insufficient air, reducing combustion, and when the damper 110 is closed, the chimney is the gas inside the furnace. Therefore, secondary air enters the kiln, and the air is sufficiently present, resulting in oxidative combustion.

[0004]

[Problems to be Solved by the Invention] However, reflecting the recent boom in pottery, demand for gas pottery kilns at pottery classes and schools has increased, and there are about 800 pottery classes in the Tokyo metropolitan area alone. It is presumed to do. Most of these pottery classes are inside a concrete structure (building) that is located near a downtown area where transportation is convenient, and inevitably there are many cases where pottery kilns are installed indoors. In order to properly use reduction firing or oxidation firing in the conventional pottery kiln that uses a Bunsen burner, as mentioned above, it is absolutely necessary to install a chimney to a certain extent to secure draft pressure, but concrete buildings are required. In the case of a pottery class that needs to be installed inside, an installation space,
Due to the limitation of the mounting method, it is not possible to install a long chimney, so it has been necessary to replace the chimney with a short exhaust hood to secure draft pressure.

The conventional draft pressure adjusting damper 11 is also used.
When the reduction and oxidative combustion in the furnace are controlled by opening and closing 0, it is difficult for an amateur to adjust the opening and closing, and there is a problem that it is not easy to maintain the temperature in the furnace at an appropriate firing temperature. Proper automatic firing is desired. However, it is necessary to control the damper at the same time as the temperature control in order to automatically fire the conventional ceramics kiln, but it is necessary to control the gas amount by temperature feedback and simultaneously control the damper opening degree. Has a problem with the sensor that determines the reduction or oxidation state, and the operation of the damper opening requires mechanical control such as a link, which is quite difficult.
Also for this, a simple and precise control method has been desired.

The present invention solves such a problem and eliminates a long chimney from a pottery kiln using a Bunsen type burner by using an ejector and eliminates fluctuation of draft pressure, which is convenient for indoor installation of the pottery kiln. The purpose is to provide a Bunsen gas pottery kiln. Another object of the present invention is to provide a Bunsen-type gas pottery kiln in which reduction and oxidation firing can be automatically controlled by a microcomputer without operating the opening of a damper.

[0007]

Bunsen according to claim 1 of the present invention
Type gas pottery kiln is a Bunsen that requires secondary air for combustion.
The type gas ceramics kiln is characterized in that an ejector E including an ejector nozzle 20 and an ejector fan 21 is installed in the flue so that secondary air for combustion can be sucked into the furnace.

The first aspect of the present invention is an alternative to the above-mentioned chimney, which is used in an in- pipe combustion immersion pipe burner using a Bunsen burner, in which an ejector is installed at the outlet of the immersion pipe and an air nozzle of the ejector is installed. A technique of supplying combustion air into a pipe (pipe) by sucking secondary combustion air from around the burner with a pressure ejected outward from the burner to complete combustion is applied to a pottery kiln. That is, the ejector nozzle 20 is installed so as to be parallel to the vertical flue located at the back of the pottery kiln, and the ejector E is connected to the ejector fan 21 provided outside so that air can be ejected from the nozzle. Set up. Then, by ejecting air from the nozzle 20, external air can be sucked into the furnace from the secondary air holes around the Bunsen burner by its back pressure, so that it can be used instead of the chimney. Therefore, a long chimney is not required, which is convenient for indoor installation of a pottery kiln. Also, since there is no long chimney that stretches outdoors, there is no change in draft pressure due to wind or season,
Stable firing is possible.

The invention of claim 2 is the bunze according to claim 1.
By changing the ejector fan pressure of the gas type ceramics kiln, the amount of the secondary air for combustion sucked can be increased or decreased to arbitrarily change the atmosphere in the ceramics kiln to an oxidized or reduced state.

The second aspect of the invention has the same effect as increasing the fan pressure of the ejector, that is, increasing the height of the chimney, so that the fan pressure of the ejector can be arbitrarily changed in the lower part of the conventional chimney. This can be done instead of manually opening and closing the damper and adjusting the secondary air that is sucked in, so that the atmosphere in the furnace can be changed to a reduced or oxidized state. Here, the reduced state means an air-deficient state in which secondary air does not enter the kiln, and the oxidized state means a state in which secondary air enters the kiln and sufficient air exists.

The invention of claim 3 is the same as that of claim 1 or 2.
When changing the gas pressure of the Bunsen gas pottery kiln, the temperature of the atmosphere in the pottery kiln can be controlled in a constant oxidation or reduction state by constantly changing the ejector fan pressure in conjunction with the gas pressure. Is.

The third aspect of the present invention is a conventional program-controlled ceramics kiln having a temperature control function only by temperature feedback, for example, the problems of Japanese Patent Application No. 6-294954.
That is, in the reduction firing, when the furnace temperature cannot follow the programmed heating curve, the temperature controller tries to release the gas to raise the temperature, which leads to further reduction. The biggest problem that it will not rise is that by changing the gas pressure at the same time as changing the ejector fan pressure, the temperature inside the ceramic kiln can be controlled in a constant reducing or oxidizing state. it can.

The invention of claim 4 is the bunze according to claim 3.
The fan pressure for the ejector of the gas type ceramics kiln is the frequency in the inverter 35, and the gas pressure is the current value of the proportional valve 33.
By controlling with the microcomputer 30, it is possible to perform oxidation or reduction firing in a fully automatic manner.

In the fourth aspect of the invention, if the fan pressure of the ejector is controlled by the inverter 35 at the same time as the frequency of the fan motor and the gas pressure is controlled at the same time as the current value of the proportional valve, the temperature, the reducing and oxidizing atmospheres can be automatically controlled. Can be Since it is possible to control the program by the microcomputer, the oxidation and reduction firing can be automated in a pattern that follows professional firing, just by pressing the setting button like home appliances.

[0015]

DETAILED DESCRIPTION OF THE INVENTION An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a half-section front view showing a Bunsen type gas pottery kiln of the present invention, FIG. 2 is a longitudinal side view of the same, FIG. 3 is an enlarged sectional view of a combustion section, FIG. 4 is a control system diagram of the pottery kiln, and FIG. it is a graph showing a ratio of gas pressure in the carbon dioxide concentration constant _(mmH 2 O) and Juan pressure _(mmH 2 O).

In FIG. 1 and FIG. 3, A is an inversion flame type ceramics kiln equipped with a Bunsen type gas burner 5 for sucking the primary air for combustion at a pressure at which fuel gas is ejected, A refractory burner block 3 provided with combustion chambers 4 on both sides of the crater 2 is installed, a gas burner 5 is installed under each combustion chamber 4, and a primary air intake 11 is provided on the gas burner 5 and copper. A gas supply pipe 7 is connected via a pipe 6. The gap between the crater 2 and the burner head 5a becomes the secondary air hole 12. Reference numeral 9 is a spark plug, and 10 is a frame rod. The furnace hearth 1 of the kiln is provided with a draw hole 13 for discharging the exhaust gas inside the furnace to the flue, a horizontal flue 14 is provided on the lower surface of the hearth 1, and the horizontal flue 14 is provided on the side of the furnace. The vertical flue 15 is formed continuously. Reference numeral 16 is an opening / closing door which is opened and closed by turning a handle. Reference numeral 17 is a blocking plate that prevents heat from escaping when the fire is stopped, and is provided so as to open and close the flue by advancing and retreating from the upper side of the vertical flue 15.

1 to 4, the pottery kiln A of the present invention is shown.
In place of the long chimney, an ejector E including an ejector nozzle 20 and an ejector fan 21 is provided in the vertical flue 15 of the pottery kiln A having the above-mentioned configuration, and the ejector E can be automatically controlled. . As the ejector E, in the embodiment, an ejector nozzle 20 is provided in parallel with the vertical flue 15 penetrating the bottom of the kiln A, and an external ejector fan 21 is connected to the nozzle 20 so that the air above the nozzle 20 is discharged. To squirt. The nozzle 20 is provided at the bottom in FIG.
The invention is not limited to this, and may be provided so as to penetrate from the side as shown in FIG. In this case, the tip of the nozzle ejects air upward along the vertical flue. Since the vertical flue 15 is equipped with the ejector E, it is not necessary to provide a long chimney, and the tip of the vertical flue 15 is 30 cm directly.
A short exhaust stack 22 is provided. A draft pressure can be secured by the action of the ejector E and the exhaust pipe 22. An exhaust hood 23 is attached to a wall surface 24 above the exhaust pipe 22. The hood 23 sufficiently sucks the exhaust gas and ambient air, cools the high-temperature exhaust gas, and discharges it to the outside. An exhaust pipe 25 of the hood 23 is provided so as not to be affected by wind pressure. Reference numeral 26 is a heat insulating material, for example, spectacle stone. An inverter 35 described later is connected to the external ejector fan 21, and the frequency of the inverter 35 is controlled by a microcomputer controller (commonly known as a microcomputer) 30 to control the fan pressure of the ejector fan 21. Further, an electromagnetic valve 34 is provided downstream of the primary air intake 11 of the gas burner 5, a gas proportional valve 33 described later is connected, and a current value of the proportional valve 33 is controlled by a proportional valve driver 32 according to a command from the microcomputer 30. And the gas pressure is controlled.

In FIG. 4, a microcomputer 30 for controlling the temperature of the pottery kiln and the atmosphere of reduction and oxidation is provided with a built-in inverter 35. That is, a thermocouple 31 is provided in the upper part of the pottery kiln, a temperature controller, a sequencer, etc. are built in the microcomputer 30, the thermocouple 31 and the microcomputer 30 are connected in association, and the microcomputer 30 has a proportional valve driver 32 and a gas proportional valve. 33 is connected to the solenoid valve 34 of the Bunsen type gas burner, the gas pressure is controlled by the microcomputer 30 by controlling the current value of the proportional valve, and the inverter 35 built in the microcomputer 30 is connected to the ejector fan 21 provided with the ejector nozzle 20. The ejector fan pressure is controlled by changing the frequency of the fan motor with the inverter 35, and oxidation or reduction firing can be performed automatically and program control can be performed.

The fan pressure for the ejector of the Bunsen gas pottery kiln uses an inverter to control the frequency of the fan motor and
The method of controlling the gas pressure simultaneously with the current value of the proportional valve is as follows. Graph in Figure 5, capable of maintaining the reduction from the experimental data for a number of reduction firing (carbon monoxide concentration is constant) Gas pressure (mmH 2 _O) and the ratio of the ejector for fan pressure (mmH 2 _O) A graph is shown. The carbon monoxide concentration in this graph is 3.0% and 3.5%, and shows the ratio of the gas pressure and the fan pressure when they are constant. The concentration of carbon monoxide is not limited to this, and the ratio of gas pressure to fan pressure can be determined by the concentration of carbon monoxide suitable for it in the pottery kiln. From this graph relationship, further with the current value of the gas proportional valve,
Create a formula with the ejector's fan frequency, register it in the microcomputer, and use the registered data as a reference. As an actual method, the temperature input from the thermocouple 31 attached to the furnace is converted into 4-20 mA by the temperature controller and is taken into the microcomputer 30. The proportional valve 33 is 4-2 from the microcomputer.
Output 0 mA and control the gas pressure with the proportional valve driver 32. The ejector outputs 4-20 mA from the microcomputer and controls the frequency of the inverter 35 to control the rotation speed of the ejector fan 21. In this manner, the outputs of the proportional valve and the ejector are sequentially changed according to the data registered in the microcomputer, and the gas pressure and the fan pressure are changed. In this way, if the measured value is lower than the set temperature of the program, the gas pressure and the ejector fan pressure are increased by 1 point. This is repeated every few seconds (variable) to raise the temperature, but if the measured value is lower, the point is raised and the point is raised until it reaches the set value. On the contrary, when the measured value becomes higher than the set value, the output is lowered by 1 point, and the point is continuously lowered until the set value is reached. In this way, program control became possible. The pottery kiln is program controlled by a microcomputer, and pushes a setting button to oxidize up to 1300 ° C in a minimum of 8 hours.
Reduction combustion can be done freely.

According to the present invention having the above-mentioned structure, by ejecting air from the nozzle of the ejector installed in the flue, the back pressure can suck external air into the furnace from the secondary air holes around the Bunsen burner. Moreover, the atmosphere in the furnace can be appropriately changed to the reduced or oxidized state by arbitrarily changing the fan pressure of the ejector. At the same time, the air ejected by the ejector fan can lower the temperature of the exhaust gas, and at the same time, carbon monoxide in the exhaust gas generated during reduction firing can be burned in the vertical flue. Furthermore, by adopting an ejector,
Instead of the conventional mechanical control of damper opening, frequency control of the ejector fan motor is all that is required, which makes control very easy, and in the end, the gas pressure is proportional valve for temperature control. Feedback control,
Since it became possible to control with high precision the microcomputer to change the fan pressure at the same time, which can maintain the appropriate reduction each time the gas pressure changed, with the microcomputer, it became possible to control the temperature and reduction program. Oxidation firing was also possible with the same method. With the program control by the microcomputer, you can freely oxidize and reduce combustion up to 1300 ℃ in a minimum of 8 hours by pressing the setting button. Therefore, since it can be automated in a pattern that follows professional baking,
Even a layman can make a work created at a school like a professional.

Although the above embodiment has been described, the present invention is not limited to this embodiment, and various embodiments can be implemented without departing from the gist of the present invention.

[0022]

According to the first aspect of the present invention, by ejecting air from the nozzle of the ejector installed in the flue, the back pressure thereof causes the external air from the secondary air hole around the Bunsen type burner to burn the outside air into the furnace. As it can be sucked in, it can be used instead of a chimney. Therefore, since a long chimney is not required, the pottery kiln can be easily installed indoors. Since there is no long chimney that grows outdoors, there is no change in draft pressure due to wind or season, so stable firing can be done throughout the year.

As a result of eliminating the chimney and adopting an ejector, program control by a microcomputer became possible, so by pressing the setting button like home appliances, oxidation,
Reduction firing can be done freely. The air ejected by the ejector fan can lower the temperature of the exhaust gas, and at the same time, carbon monoxide in the exhaust gas generated during reduction firing can be burned in the vertical flue.

According to the second aspect of the present invention, increasing the fan pressure of the ejector has the same effect as increasing the height of the chimney. Therefore, eventually changing the fan pressure of the ejector reduces the atmosphere in the furnace. , Can be changed to oxidation state.

According to the third aspect of the present invention, temperature control can be performed in a constant reduction or oxidation state by changing the gas pressure and the fan pressure of the ejector in conjunction therewith.

According to the invention of claim 4, if the fan pressure of the ejector is controlled by the inverter at the frequency of the fan motor and the gas pressure is controlled by the current value of the proportional valve at the same time, the
It is possible to automatically control the oxidizing atmosphere. In order to control the temperature, the gas pressure is feedback-controlled with a proportional valve, and the fan pressure that can maintain the corresponding reduction each time the gas pressure changes can be changed simultaneously with the inverter, so it can be controlled with high precision by the microcomputer, Program control is possible. Since it is possible to control the program using a microcomputer, you can automate oxidation and reduction firing in a pattern that follows professional firing, just by pressing a setting button like home appliances, and you can make pottery works in a pottery class, school etc. However, it is convenient because it can be baked like a professional.

[Brief description of drawings]

FIG. 1 is a semi-sectional front view showing a Bunsen-type gas pottery kiln of the present invention.

FIG. 2 is a vertical sectional side view of the same.

FIG. 3 is an enlarged sectional view of a combustion section.

FIG. 4 is a control system diagram of a pottery kiln.

FIG. 5: Gas pressure (mmH _{2 at} constant carbon monoxide concentration)
O) and a graph showing the ratio of the fan pressure _(mmH 2 O).

FIG. 6 is a vertical sectional side view of a conventional pottery kiln.

FIG. 7 is a rear view of the same.

[Explanation of symbols]

1 hearth 2 crater 3 burner block 5 gas burners 14 Horizontal flue 15 vertical flue 20 ejector nozzle 21 Ejector fan 22 Exhaust stack 30 microcomputer 32 proportional valve driver 33 gas proportional valve 35 inverter

─────────────────────────────────────────────────── ─── Continuation of front page (72) Haruki Narita 11-11 Higashimatsuyama-cho, Seto City, Aichi Prefecture-3 (72) Hidenobu Takada 2-14-4 Minamigaoka, Nisshin City, Aichi Prefecture (72) Inventor Yoshihide Ichikawa No. 515, Nanbu, Kitashin-cho, Nisshin-shi, Aichi (56) References JP 10-231167 (JP, A) JP 8-189632 (JP, A) JP 5-172470 (JP, A) Actual Kaihei 3-6293 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) C04B 33/32 F27D 7/00

Claims (4)

(57) [Claims] 1. A Bunsen type gas ceramics kiln requiring secondary air for combustion, wherein an ejector is installed in a flue so that secondary air for combustion can be sucked into the furnace. Characteristic Bunsen
Type gas pottery kiln. 2. The ejector fan pressure is changed to increase or decrease the suctioned secondary air amount for combustion, whereby the atmosphere in the pottery kiln can be arbitrarily changed to an oxidized or reduced state. Bunsen gas pottery kiln described. 3. When the gas pressure is changed, the ejector fan pressure is always changed in association with the gas pressure, thereby making it possible to control the temperature in a constant oxidizing or reducing state of the atmosphere in the ceramics kiln. according to claim 1 or 2 of the probe, characterized
Nsen gas pottery kiln. 4. The ejector fan pressure is controlled by an inverter and the gas pressure is controlled by a microcomputer, and the gas pressure is controlled by a current value of a proportional valve. Bunsen gas pottery kiln.