JPH1163843A - Method for controlling temperature in baking furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a controlling method for holding a combustion condition in a baking furnace to an appropriate combustion condition by automatically maintaining a combustion air feed quantity to be fed into a burner to an appropriate quantity preset. SOLUTION: This method controls a temperature in a baking furnace 10 by controlling a combustion rate of a burner 12 provided in the furnace 10. By this method, combustion air is fed to the burner 12 from a blower 18 through a feed pipe passage 16 and, simultaneously, the pressure of the combustion air fed through the feed pipe passage 16 is detected by a pressure sensor 32. The number of rotations of the blower 18 are controlled by a pressure regulator 34 through an inverter 36 so that the pressure detected by the pressure sensor 32 shows a certain pressure preset correspondingly to an appropriate feed quantity of combustion air. Further, the pressure sensor 32 is housed in a constant temperature chamber 38, and an atmospheric temperature around the pressure sensor 32 is kept at a constant level.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for controlling the temperature in a firing furnace.

[0002]

2. Description of the Related Art In a firing furnace for firing tiles, sanitary ware, and other so-called pottery, a large number of burners are attached to a combustion zone, and the inside of the furnace is heated by the combustion heat of the burners to maintain a predetermined temperature. ing.

Here, the appropriate combustion state of the burner changes depending on various conditions. For example, it varies depending on the type and shape of the object to be fired, the manner of stacking in the firing furnace, the shape, the arrangement, and the like, and also changes depending on the season such as day, night, summer, and winter. Therefore, conventionally, by controlling the supply of fuel to the burner and the supply of combustion air,
The combustion state of the burner is controlled.

FIG. 5 shows this concretely.
In the figure, reference numeral 200 denotes a firing furnace, in which a number of burners 202 are mounted in a combustion zone between a pre-tropical zone and a cooling zone. Reference numeral 204 denotes a thermocouple for measuring the temperature in the firing furnace 200. The temperature detected by the thermocouple 204 is compared with an appropriate temperature set in advance by a temperature controller 206, and the difference is eliminated. The control motor 208 is operated as described above to change the opening of the fuel valve 210, whereby the burner 20 is supplied through the supply line 212.
2 to control the amount of fuel sent.

At the same time, the supply line 2 is
The amount of combustion air supplied to the burner 202 through the blower 16 is controlled by the blower damper 2 provided on the supply pipe 216.
The opening 18 is adjusted to an appropriate amount corresponding to the fuel supply amount. In addition, 220 is a hand damper.

Here, the fuel supply line 212 and the combustion air supply line 216 are a common line for many burners 202, and the fuel and combustion air are common for many burners 202. The pipelines 212 and 216
It is supplied through.

[0007]

As described above, in the related art, by keeping the rotation speed of the blower 214 constant and adjusting the blower damper opening on the supply line 216,
The supply amount of combustion air to the burner 202 is adjusted, and the opening degree of the blower damper 218 is manually adjusted by an operator.

However, the control of the supply amount of combustion air by adjusting the opening of the blower damper 218 by such an operator involves changes in the type and shape of the fired product, changes in the form in the firing furnace, and changes in the firing furnace. Changes in the amount of incoming products to be fired,
It is not possible to sufficiently cope with changes in the ambient temperature during the day and night, and therefore, the combustion conditions of each burner 202 cannot always be maintained in an appropriate combustion state. It is a fact that firing failure such as insufficient firing or insufficient firing has occurred.

It is particularly difficult to cope with fluctuations in the air supply amount of the blower 214 due to fluctuations in the power supply voltage due to load fluctuations during daytime and nighttime operation, and this also causes the above-mentioned firing failure. Had become. In addition, in the case of the conventional method, there is a problem that much labor and time are required for adjusting the opening degree of the blower damper 218.

[0010]

The invention of the present application has been made to solve such a problem. According to a first aspect of the present invention, there is provided a method for controlling the temperature inside a firing furnace by controlling the combustion of a burner provided in the firing furnace, wherein a combustion air is supplied from a blower to the burner through a supply pipe. At the same time, the pressure of the combustion air sent through the supply line is detected by a pressure sensor, and the rotation speed is adjusted so that the pressure detected by the pressure sensor becomes a set pressure corresponding to an appropriate supply amount of the combustion air. The control means controls the rotation speed of the blower.

A method according to a second aspect is characterized in that, in the first aspect, the pressure sensor is housed in a constant temperature chamber, and the ambient temperature around the pressure sensor is maintained at a constant temperature.

According to a third aspect of the present invention, in the method of the second aspect, a heater and a temperature sensor are disposed in the constant temperature chamber, and the temperature sensor detects the temperature in the constant temperature chamber and uses the heater based on the detected temperature. The heating in the constant temperature chamber is controlled to maintain the constant temperature state in the constant temperature chamber.

According to a fourth aspect of the present invention, the air in the firing furnace is exhausted through an exhaust duct and an exhaust blower, and the pressure in the firing furnace or the pressure in the exhaust duct is detected by a pressure sensor. The rotation speed control means controls the rotation speed of the exhaust blower so that the internal pressure is maintained at a set appropriate pressure or the pressure in the exhaust duct is maintained at a set pressure corresponding to the appropriate pressure. By performing this, the temperature in the firing furnace is controlled.

[0014]

As described above, according to the control method of the first aspect, the pressure of the combustion air sent through the supply pipe by the blower is detected by the pressure sensor, and the pressure detected by the pressure sensor is adjusted to an appropriate level. According to the control method, the number of rotations of the blower is controlled by the number-of-rotations control means so that the set pressure corresponds to the supply amount of the combustion air. When changing the supply amount of combustion air to the burner according to the change of the form of stacking, the shape, the arrangement, etc., or the change of season such as day, night or summer, winter, etc., simply change the above set pressure value. Thus, the supply amount of combustion air sent to the burner can always be maintained at an appropriate amount.

As a result, the temperature fluctuation in the firing furnace can be made as small as possible, and the occurrence of firing defects such as the above-mentioned overheating and insufficient firing can be reduced as much as possible.

Further, according to the control method of the present invention, even if the power supply voltage fluctuates due to a load fluctuation or the like, the rotation speed of the blower automatically changes, and the supply amount of combustion air to the burner becomes an appropriate amount. Since the temperature is held, it is possible to prevent a temperature change in the firing furnace caused by such a change in the power supply voltage, and it is possible to fire the firing target satisfactorily.

In addition, according to the control method of the present invention, it is not necessary for an operator to adjust the opening of the blower damper every time the supply of combustion air to the burner needs to be changed, which is necessary. The labor and time can be reduced.

That is, conventionally, manual operation was required for the burner combustion control. However, according to the present invention, this can be eliminated, and the burner combustion control can be performed automatically.

Incidentally, the above pressure sensor has a problem that the detected pressure value fluctuates when the ambient temperature around the sensor changes. Here, the control method according to the second aspect is such that the pressure sensor is housed in a constant temperature chamber, and the ambient temperature around the sensor is maintained at a constant temperature. The pressure of the working air can be accurately detected, and the burner combustion and the temperature control in the firing furnace can be more accurately performed.

According to a third aspect of the present invention, a heater and a temperature sensor are disposed in the constant temperature chamber, and while the temperature sensor detects the temperature in the constant temperature chamber, the operation of the heater is controlled based on the detected temperature, and the constant temperature chamber is controlled. It is kept at a constant temperature,
With this configuration, the temperature in the constant temperature chamber can be easily and accurately maintained at an appropriate temperature.

By the way, in the firing furnace, the inside of the furnace is exhausted by an exhaust blower through an exhaust duct. At this time, keeping the temperature distribution and the pressure gradient in the firing furnace constant maintains proper firing conditions. Needed above.

According to a fourth aspect of the present invention, the pressure of a predetermined portion in the firing furnace is maintained at an appropriate pressure by controlling the number of revolutions of the exhaust blower. By performing evacuation in the firing furnace through, it is possible to prevent the firing conditions in the firing furnace from fluctuating, and it is possible to always maintain the firing conditions in the firing furnace at appropriate firing conditions. The occurrence of poor firing such as insufficient firing can be suppressed.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described in detail with reference to the drawings. In FIG. 1, reference numeral 10 denotes a firing furnace, and a number of burners 1 are provided in a combustion zone between a pre-tropical zone on the inlet side and a cooling zone on the outlet side.
2 are provided. Then, fuel is sent to the burner 12 through a supply pipe 14, and combustion air is supplied by a blower 18 through a supply pipe 16. The supply of fuel and combustion air to each burner 12 is commonly performed through common pipes 14 and 16.

A blower damper 20 is provided on the combustion air supply line 16. In this example, the blower damper 20 is held in a fully opened state. In addition, 22 is a hand damper, and 23 is a pressure gauge.

Numeral 24 denotes a thermocouple as a temperature sensor for detecting the temperature inside the firing furnace 10 (combustion zone). Based on the temperature detected by the thermocouple 24, the temperature controller 2
6 operates the control motor 28 to change the opening or opening / closing of the valve 30 on the fuel supply line 14.

More specifically, the temperature controller 26 compares the temperature detected by the thermocouple 24 with a preset set temperature (appropriate temperature), and adjusts the temperature so that the detected temperature becomes the set temperature. The heater 26 operates the control motor 28 to adjust and control the opening or opening / closing of the valve 30.

Reference numeral 32 denotes a pressure sensor for detecting the pressure of the combustion air in the supply pipe 16. The detected pressure is converted into an electric signal and output to the pressure regulator 34.

The pressure regulator 34 compares the pressure detected by the pressure sensor 32 with a preset pressure, that is, a preset pressure corresponding to an appropriate amount of combustion air to be supplied to the burner 12. And the rotation speed (rotation speed) of the blower 18 via the inverter 36 according to the difference.
Is increased or decreased.

That is, the pressure regulator 34 increases or decreases the rotation speed of the blower 18 so that the pressure detected by the pressure sensor 32 becomes a set pressure corresponding to an appropriate air supply amount. In this embodiment, the pressure regulator 34 constitutes a rotation speed control means.

In this embodiment, the pressure sensor 32 is
8, the ambient temperature around the pressure sensor 32 is kept constant. Specifically, a thermocouple 40 as a temperature sensor is arranged in the constant temperature chamber 38, and the temperature in the constant temperature chamber 38 is detected by the thermocouple 40. The detected temperature is converted into an electric signal and output to the temperature controller 42.

The temperature controller 42 compares the temperature detected by the thermocouple 40 with a preset proper temperature (set temperature), and according to the difference, a heater 46 via an SSR (solid state relay) 44. Is controlled, and the temperature in the constant temperature chamber 38 is always maintained at the set appropriate temperature.

As described above, in this embodiment, the blower damper 2 which has been conventionally adjusted in opening for controlling the supply amount of combustion air is provided.
0 is fully opened, and instead the air pressure of the supply pipe line 16 is detected by the pressure sensor 32, and the blower 1 is set so that the detected pressure becomes a pressure corresponding to an appropriate air supply amount.
8 is controlled.

According to this control method, the type and shape of the product to be fired, the manner of stacking in the firing furnace 10, the shape, the arrangement, and the like, or the seasonal change such as day, night, summer, winter, etc. Accordingly, when the supply amount of the combustion air to the burner 12 is changed, the supply amount of the combustion air to be sent to the burner 12 can always be maintained at an appropriate amount by simply changing the set pressure value. .

Thus, the temperature fluctuation in the firing furnace 10 can be made as small as possible, and the occurrence of defective firing such as the above-mentioned overheating and insufficient firing can be reduced as much as possible.

Further, according to the control method of this embodiment, even if the power supply voltage fluctuates due to a load fluctuation or the like, the blower 18 is automatically turned on.
The rotation speed of the burner 12 changes to keep the amount of combustion air supplied to the burner 12 constant, so that the temperature change in the firing furnace 10 due to the fluctuation of the power supply voltage can be prevented, and the firing target can be satisfactorily fired can do.

In addition, according to the control method of this embodiment, the burner 1
The operator does not need to adjust the opening of the damper 20 every time the supply amount of the combustion air to the fuel cell 2 needs to be changed, so that the labor and time required for the adjustment can be reduced.

That is, although manual work was conventionally required for controlling the combustion of the burner 12, this can be eliminated according to the present embodiment, and the combustion control of the burner 12 can be automated.

In the control method of the present embodiment, since the pressure sensor 32 is housed in the constant temperature chamber 38 and the ambient temperature around the sensor 32 is kept constant, the pressure of the combustion air sent through the supply pipe 16 is reduced. The pressure can be accurately detected, and thus, the combustion of the burner 12 and the control of the temperature in the firing furnace 10 can be performed more accurately.

According to the control method of this embodiment, in the conventional control method shown in FIG. 5, the supply pressure of the combustion air to the burner fluctuates within a range of ± 20 mmH ₂ O (center value is 627 mmH ₂ O). But ± 1 mmH ₂ O (center value is 627 mm
H ₂ O).

FIG. 2 shows temperature fluctuations in the firing furnace 10 (combustion zone) when the supply of combustion air to the burner 12 is controlled by the control method shown in FIG. 1, and FIG. 3 shows temperature fluctuations when the supply of combustion air is controlled by the conventional control method shown in FIG.

However, in these figures, the temperature curves A and A 'are the detected temperature curves of the thermocouple a at the same point, and B and B' are the detected temperature curves of the thermocouple b at the other points.
C and C ′ represent the temperature curves detected by the other thermocouple c,
D 'also represents a temperature curve detected by another thermocouple d. As is clear from the comparison of these figures,
According to the control method of this embodiment, the temperature fluctuation in the furnace can be suppressed to a small value.

FIG. 4 shows another embodiment.
Reference numeral 8 denotes an exhaust duct for exhausting air from near the inlet of the firing furnace 10, and reference numeral 50 denotes an exhaust blower provided on the exhaust duct 48. Other points are the same as those in FIG.

In this example, however, the pressure inside the furnace 10 at the boundary between the pre-tropical zone and the combustion zone is detected by the pressure sensor 32, and the detected pressure is adjusted to a preset appropriate pressure. The number of rotations of the exhaust blower 50 is controlled. Although not shown, air is supplied into the firing furnace 10 through a predetermined supply duct.

According to the control method of this embodiment, the exhaust duct 48
The evacuation of the baking furnace 10 is performed through to prevent the baking conditions in the baking furnace 10 from fluctuating, and the baking furnace 1 is always exhausted.
The firing conditions within 0 can be maintained at appropriate firing conditions, and the occurrence of firing defects such as the above-mentioned overheating and insufficient firing can be suppressed.

Although the embodiment of the present invention has been described in detail, this is merely an example, and the present invention can be implemented in variously modified forms without departing from the gist thereof.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a control method according to an embodiment of the present invention.

FIG. 2 is a diagram showing a temperature fluctuation range in a furnace when the supply of combustion air is controlled by the control method of FIG. 1;

FIG. 3 is a comparative example diagram showing, as a comparative example, a fluctuation range of the furnace temperature when controlling the combustion air by the conventional control method.

FIG. 4 is an explanatory diagram of a control method according to another embodiment of the present invention.

FIG. 5 is an explanatory diagram of a conventional method for controlling combustion air.

[Explanation of symbols]

 Reference Signs List 10 firing furnace 12 burner 14, 16 supply line 18 blower 32 pressure sensor 34 pressure regulator 36 inverter 38 constant temperature chamber 40 thermocouple (temperature sensor) 46 heater 48 exhaust duct 50 exhaust blower

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI F27D 19/00 C04B 35/64 C

Claims (4)

[Claims] In a method for controlling the temperature inside a firing furnace by controlling the combustion of a burner provided in the firing furnace, combustion air is supplied to the burner from a blower through a supply pipe, and the supply pipe is supplied to the burner. The pressure of the combustion air sent through the passage is detected by a pressure sensor, and the blower is controlled by the rotation speed control means so that the pressure detected by the pressure sensor becomes a set pressure corresponding to an appropriate supply amount of the combustion air. A method for controlling the temperature in a firing furnace, wherein the number of rotations is controlled. 2. The method according to claim 1, wherein the pressure sensor is housed in a constant temperature chamber, and an ambient temperature around the pressure sensor is maintained at a constant temperature. 3. The constant temperature chamber according to claim 2, further comprising a heater and a temperature sensor disposed in the constant temperature chamber, wherein the temperature sensor detects the temperature in the constant temperature chamber, and the heater heats the constant temperature chamber based on the detected temperature. And controlling the temperature in the constant temperature chamber to maintain a constant temperature in the constant temperature chamber. 4. The air in the firing furnace is exhausted through an exhaust duct and an exhaust blower, and the pressure in the firing furnace or the pressure in the exhaust duct is detected by a pressure sensor, and the pressure in the firing furnace is set. By controlling the number of revolutions of the exhaust blower by means of revolution number control means so as to maintain the pressure in the exhaust duct or to maintain the pressure in the exhaust duct at a set pressure corresponding to the appropriate pressure, firing is performed. A method for controlling the temperature in a firing furnace, comprising controlling the temperature in the furnace.