JP3072412B2 - Combustion furnace combustion control system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a system for controlling combustion of a gas burner provided in a firing furnace such as a roller hearth kiln for firing tiles.

[0002]

2. Description of the Related Art Some sintering furnaces are divided into a preheating zone, a sintering zone, a cooling zone, and the like. Combustion control is performed on each gas burner arranged in each zone so that the zone temperature in the furnace maintains the set temperature. As shown in FIG. 3, the combustion control system of the firing furnace for performing the combustion control is provided in a plurality of gas burners 1 and 1 provided in the firing furnace and a gas supply pipe 2 extending from each gas burner 1 in the middle. Governor 3 for gas amount adjustment,
Back pressure chamber 3a of each gas amount adjusting governor 3 and collective air piping 5
, A back pressure setting tool 6 joined to the collective air pipe 5, and a back pressure setting tool 6 that detects the furnace temperature.
And a controller 7 for controlling the combustion of the plurality of gas burners 1 and 1.

Each gas supply pipe 2 is connected to a gas main pipe 9 via a ball valve 8 for flow control which is provided in the middle of the gas supply pipe 2. A combustion air supply pipe 10 extending from each gas burner 1 is connected to a zone air pipe 12 via a flow control butterfly valve 11 provided in the middle of the combustion air supply pipe 10.
The zone air pipe 12 is connected to an air main pipe 14 via a flow rate adjusting butterfly valve 13 arranged on the way.

[0004] The collective air pipe 5 is connected to the zone air pipe 1.
2, and a back pressure setting device 6 composed of a relief butterfly valve is connected in the middle. The back pressure setting tool 6 controls the opening / closing degree of the butterfly valve body with the controller 7 to adjust the air pressure supplied to the branch air pipe 4 by increasing or decreasing the amount of air supplied from the zone air pipe 12 to the atmosphere. Is what you do. When the zone temperature in the furnace falls, the combustion control system reduces the opening of the back pressure setting tool 6 by the controller 7 to increase the air pressure supplied to the branch air pipe 4, thereby increasing the back pressure chamber of each governor 3. 3
a (see FIG. 4), the opening degree of the flow control valve 3b built in the governor 3 is increased, and each burner 1
The supply amount of the fuel gas is increased. Conversely, when the temperature in the furnace rises, the controller 7 opens the back pressure setting tool 6 to lower the air pressure supplied to the branch air pipe 4, thereby reducing the pressure in the back pressure chamber 3 a of each governor 3. Then, the opening degree of the flow control valve 3b of the governor 3 is reduced, and the supply amount of the fuel gas to each burner 1 is reduced.

[0005]

The butterfly valve used for the back pressure setting device 6 has a region where the flow rate changes extremely with respect to the change in the rotation angle of the butterfly, so that the amount of relief is delicately controlled. It is difficult. as a result,
In the conventional system, the fuel gas amount adjustment range is extremely narrow,
It may not be able to follow the temperature change of the controlled zone,
Further, the temperature control of other zones may be adversely affected. Therefore, in the conventional system, the yield of the fired product may be extremely deteriorated.

Accordingly, an object of the present invention is to provide a combustion control system for a firing furnace capable of widening a fuel gas amount adjustment range in order to solve the above problem.

[0007]

The gist of the present invention is that a plurality of gas burners provided in a firing furnace and a gas amount adjusting device provided in the middle of a gas supply pipe extending from each gas burner. A branch air pipe that joins the governor, the back pressure chamber of each governor for gas amount adjustment, and the collecting air pipe, a back pressure setting tool that joins the collecting air pipe, and a back pressure setting tool that detects the temperature inside the furnace In the combustion control system of the firing furnace having a controller to operate, the back pressure setting tool is a variable governor disposed in the middle of the collecting air pipe, and an air release tool joined to the collecting air pipe downstream of the variable governor. And a pressure control tool provided on the variable governor is operated by the controller. The gist of the present invention according to claim 2 is that the pressure setting tool includes a seat for a diaphragm pressing coil spring built in the variable governor and an adjusting screw for changing a position of the seat along a compression direction of the coil spring. 2. The combustion control system for a firing furnace according to claim 1, wherein an adjustment screw is rotated by the controller.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a combustion control system for a firing furnace according to the present invention (hereinafter, referred to as "the present invention system") will be described based on the embodiment shown in FIGS. The improvement of the system of the present invention is, as shown in FIG.
6 is a variable governor 1 arranged in the middle of the collecting air pipe 19.
7 and an air release device 18 joined to the collective air pipe 19 on the downstream side of the variable governor 17.
Is to be operated by the controller 7. The configuration other than the improved point is substantially the same as the conventional configuration, and the same reference numerals denote the same components.

The collective air pipe 19 has a start end 19a joined to the zone air pipe 12 and an end 19b joined to the branch air pipe 4. The collective air pipe 19 joins a strainer 20 upstream of the variable governor 17, and connects an upstream side of the strainer 20 and a downstream side of the air release device 18 by a bypass pipe 21 with a valve. The bypass pipe with valve 21 is normally closed, and when the variable governor 17 or the controller 7 fails, the valve is manually opened to supply air at an appropriate pressure to the branch air pipe 4. When using the bypass pipe 21 with a valve, the valve 2
2, 23 are closed.

The air release device 18 is constituted by a needle valve or the like, and is for releasing a small amount of air so that air supplied from the zone air pipe 12 always flows through the variable governor 17. Variable governor 1
7, a casing 25 having an air flow passage 24, a valve seat 30 formed in the air flow passage 24, and an upper pressure setting chamber 25a and a lower air chamber 25b formed inside the casing 25 as shown in FIG. A diaphragm 26, a valve body 27 joined to the diaphragm 26, a coil spring 28 and a pressure setting tool 29 built in a pressure setting chamber 27a.

The variable governor 17 communicates the downstream side 24a of the air flow path 24 with the air chamber 25b through a communication hole 31. When the amount of air flowing through the air flow path 24 is small or zero, compression of the coil spring 28 is performed. By pressing the valve body 27 downward by force, the opening between the valve seat 30 and the valve body 27 is increased, and conversely, when a large amount of air flows through the air passage 24, the air flows into the air chamber 25b. Pneumatic diaphragm 26
Is pressed against the compression force of the coil spring 28, thereby lifting the valve body 27 upward to reduce the opening. The variable governor 17 controls the compression force of the coil spring 28 and the air chamber 25.
The valve body 27 stops in a state where the air pressure of b is balanced, and the amount of air flowing through the air flow path 24 is kept constant, so that the air pressure supplied to the branch air pipe 4 is maintained at the set pressure.

The pressure setting tool 29 of the variable governor 17 includes:
Coil spring 28 that presses diaphragm 26 in the valve opening direction
And an adjusting screw 33 for changing the position of the receiving seat 32 along the compression direction of the coil spring 28. By rotating the adjusting screw 33, the vertical position of the receiving seat 32 is changed, Adjust the compression force. The pressure setting tool 29 increases the air pressure supplied to the branch air pipe 4 by increasing the amount of air flowing through the air flow path 24 when the compression force of the coil spring 28 is increased by pushing down the receiving seat 32, and conversely, When the seat 32 is lifted to reduce the compression force of the coil spring 28, the amount of air flowing through the air flow path 24 is reduced, so that the branch air pipe 4
Decrease the air pressure supplied to.

When the zone temperature in the furnace decreases, the controller 7 controls the seat 32 of the variable governor 17 by the controller 7.
Is pushed down to increase the air pressure supplied to the branch air pipe 4, so that the back pressure chamber 3a of the governor 3 of each gas burner 1 is increased.
Is increased to increase the opening degree of the flow control valve 3b incorporated in the governor 3 to increase the supply amount of the fuel gas to each burner 1. Conversely, when the temperature in the furnace rises, the controller 7 raises the seat 32 of the variable governor 17 to lower the air pressure supplied to the branch air pipe 4, thereby lowering the pressure in the back pressure chamber 3 a of each governor 3. Let
The amount of fuel gas supplied to each burner 1 is reduced by reducing the opening of the flow control valve 3 b of the governor 3.

In the variable governor 17, since the compression force of the coil spring 28 increases and decreases in proportion to the amount of vertical displacement of the seat 32, the range of adjustment of the air pressure supplied to the branch air pipe 4 also becomes wide. As a result, in the system of the present invention, the adjustment range of the fuel gas amount becomes wide, and it is possible to follow a delicate temperature change in the control zone, and it does not adversely affect the temperature management in other zones.

[0015]

As described above in detail, the system of the present invention has an excellent effect that the yield of burned products can be remarkably improved because the fuel gas amount adjustment range can be widened.

[Brief description of the drawings]

FIG. 1 is a piping diagram showing an embodiment of a combustion control system for a firing furnace according to the present invention.

FIG. 2 is an enlarged sectional view showing a variable governor.

FIG. 3 is a piping diagram showing an embodiment of a conventional combustion control system for a firing furnace.

FIG. 4 is an enlarged sectional view showing a governor for gas amount adjustment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Gas burner 2 ... Gas supply pipe 3 ... Governor for gas amount control 3a ... Back pressure chamber 4 ... Branch air piping 7 ... Controller 716 ... Back pressure setting tool 17 ... Variable governor 18 ... Air escape tool 19 ... Collective air piping 26 ... diaphragm 28 ... coil spring 29 ... pressure setting tool 33 ... adjustment screw 32 ... seat

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F23N 1/00 103 F27D 19/00 F16K 31/12-31/128

Claims (2)

(57) [Claims] A plurality of gas burners disposed in a firing furnace;
Connected to the gas supply governor provided in the middle of the gas supply pipe extending from each gas burner, to the branch air piping that connects the back pressure chamber of each gas control governor and the collective air piping, and to the collective air piping In a combustion control system for a firing furnace comprising a back pressure setting device and a controller for operating the back pressure setting device by detecting the temperature in the furnace, the back pressure setting device is a variable disposed in the middle of the collecting air piping. A combustion control system for a firing furnace, wherein a governor and an air release device joined to a collective air pipe downstream of the variable governor are used, and a pressure setting device provided on the variable governor is operated by the controller. . 2. The pressure setting device includes a seat for a diaphragm pressing coil spring built in the variable governor, and an adjusting screw for changing a position of the seat along a compression direction of the coil spring. The combustion control system for a firing furnace according to claim 1, wherein the combustion control system is rotated by a controller.