JPH0468536B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a combustion control device for a gun-type burner, and more particularly to a combustion control device for a gun-type burner that adjusts the amount of combustion using a needle valve.

[Prior Art] A gun-type burner has been proposed in which the amount of fuel pumped from a pump and injected from a nozzle is adjusted by a needle valve connected to the pump and the nozzle, thereby changing the amount of combustion. (One example is Japanese Patent Application No. 1983-099036).

In this type of gun-type burner, the fuel injection amount changes by moving the needle valve, so there is an advantage that the combustion amount can be continuously adjusted in a stepless manner during combustion with the gun-type burner.

[Problems to be Solved by the Invention] By the way, when starting a gun-type burner, if the amount of fuel injected from the nozzle is set to a small amount, there is a problem that the atomized fuel particles are coarse and difficult to ignite. be. Therefore, when starting a gun-type burner, it is desirable to ignite after adjusting the fuel injection amount to the optimum amount for ignition.

However, after measuring outside air conditions such as air temperature or pump feeding pressure, etc., the optimal fuel injection amount at ignition is set based on these conditions, and the fuel injected from the nozzle is set at this optimal fuel injection amount at ignition. If the needle valve is activated in advance so that the structure is complicated, the number of parts increases, and the cost increases.

The present invention takes the above-mentioned facts into account, and provides a combustion control device that can easily ignite a gun-type burner that adjusts the fuel injection amount using a needle valve, regardless of whether it is started or restarted after extinguishing the flame. It is a purpose.

[Means for Solving the Problems] The combustion control device for a gun-type burner according to the present invention is used in a gun-type burner that measures the pressure-fed fuel using a needle valve and then injects it from a nozzle and burns it. The combustion control device includes an ignition means for igniting the fuel injected from the nozzle, a detection means for detecting whether or not combustion is in progress, and an ignition means for activating the ignition means when it is detected that combustion is not in progress. A moving means is provided for moving the needle valve in a direction in which the amount of fuel injected from the nozzle increases.

[Operation] In the combustion control device for a gun-type burner configured as described above, the fuel injected from the nozzle is ignited by the ignition means, and the ignition state is detected by the detection means. At this time of ignition, the needle valve is moved by the moving means to increase the fuel injection amount. Therefore, the fuel is easily atomized, and the ignitability of the ignition means is improved.

[Embodiment] FIG. 1 shows a schematic sectional view of a gun type burner according to an embodiment of the present invention.

Draft tube 12 of gun type burner 10
A nozzle 16 is fixed by a stay 14. A nozzle hole 18 for spraying fuel is provided at the tip of the nozzle 16. Also, inside the nozzle 16, there is a small diameter fuel passage 20 and a large diameter fuel passage 2 that communicate with the nozzle hole 18.
2 is formed. A supply passage 24 is communicated with the small diameter fuel passage 20, and one end of a pipe 26 is connected to the supply passage 24. The other end of the pipe 26 is connected to a fuel pump 28, through which fuel is fed. On the other hand, a return passage 30 is communicated with the large-diameter fuel passage 22, and one end of a pipe 32 is connected to the return passage 30. Therefore, the fuel sent from the fuel pump 28 is sent to the nozzle hole 18 through the small diameter fuel passage 20, and a portion is returned to the fuel tank 33 from the return passage 30 through the large diameter fuel passage 22. It's summery.

A valve body 34 is arranged within the large-diameter fuel passage 22 . The valve body 34 is rod-shaped and has a tapered needle portion 36 at its tip, and the needle portion 36 is located at the opening of the small-diameter fuel passage 20 . Valve body 34
A threaded portion 38 is formed in the middle portion of the fuel passage 22, and is screwed into a threaded groove formed on the inner circumferential wall of the large-diameter fuel passage 22. Therefore, when the valve body 34 rotates, the threaded portion 38 is guided and moved in the axial direction. When the valve body 34 moves in the axial direction, the needle portion 36 moves toward and away from the opening of the small diameter fuel passage 20, and its substantial opening area changes. Therefore, the amount of fuel supplied from the supply path 24 and returned from the large-diameter fuel path 22 via the return path 30 changes, and as a result, the amount of fuel injected from the nozzle hole 18 also changes. .

The other end of the valve body 34 is a rod portion 42 that projects rearward from the partition wall 40, and an air damper 44 is attached to the rod portion 42. The air damper 44 rotates together with the valve body 34 to change the substantial opening area of the opening 46 formed in the partition wall 40.

The rear end of the rod portion 42 is connected to a needle valve operating motor 52 via a joint 48 and a joint 50.
is connected to.

A fan 5 is installed in the center of the gun type burner 10.
4 is placed. The fan 54 is fixed to the rotating shaft of a fan motor 56.
6, it rotates at a constant rate to suck and feed combustion air. Combustion air flows into the gun-type burner 10 and, after passing through the opening 46, is fed in the direction of the nozzle nozzle 16. An ignition rod 58 is attached directly above the nozzle 16 by a stay 14 in the same manner as the nozzle 16. The ignition rod 58 is a high-voltage discharge ignition part, and the discharge part at the tip is located immediately above the nozzle hole 18 of the nozzle 16. The ignition rod 58 is connected to an ignition transformer 60 for generating high voltage, which is arranged outside the draft tube 12.

Inside the tip opening of the draft tube 12,
A frame holder 62 is attached. The frame holder 62 is a cylindrical member having a substantially truncated conical shape, and is arranged such that a small diameter opening faces the nozzle 16 and a large diameter opening faces the tip opening of the draft tube 12 . A through hole 64 for supplying combustion air is formed in the peripheral wall of the frame holder 62, and the nozzle 1
The fuel sprayed from the fan 6 and the air fed from the fan 54 are mixed.

A flame detector (CdS) 66 is disposed near the top of the needle valve actuating motor 52, and is capable of detecting the combustion state of the gun type burner 10, that is, whether or not it is in combustion.

Now, fuel pump 28, needle valve operating motor 5
2. The fan motor 56, frame holder 62 and flame detector 66 are connected to a control device 68. As shown in FIG. 2, the control device 68 includes a central processing unit (CPU) 70, a read-only memory (ROM) 72, a random access memory (RAM) 74, an input port 76, and an output port 7.
8 and a bus 80 such as a data bus or a control bus that connects them. The flame detector 66 is connected to the input port 76, as well as a thermistor 82 for temperature setting, a high temperature thermostat 84 for detecting high temperature abnormality, and an air flow switch 86 for detecting abnormality in air volume reduction. On the other hand, a fuel pump 28, a needle valve operating motor 52, a fan motor 56, and a frame holder 62 are connected to the output port 78 via each drive circuit, and a central processing unit (CPU) 70 controls each drive circuit. It is designed to control each device. A read-only memory (ROM) 74 stores in advance a control routine program to be described later.

Next, the operation of this embodiment will be explained according to the flowchart shown in FIG.

When the operation button is operated to start the gun type burner 10, the flag is reset (F←0) in step 100. Further step 10
When burner temperature T ₀ is set in step 2, step 1
At 04, the fan motor 56 is driven and the fan 68
rotates to supply air to the frame holder 76, and at the same time, in step 106, the ignition transformer 60 is activated and the ignition rod 58 begins to discharge. Further, in step 108, it is determined based on the signal from the flame detector 66 whether or not a flame has been detected.

If a flame is detected in step 108 (that is, if a false flame exists), the process proceeds to step 110, where the ignition transformer 60 is immediately stopped, and an alarm is issued in step 112. Further, in step 114, a flame detection standby state is entered. If no flame is detected, the process proceeds to step 116, where the alarm is stopped, and further, at step 118, the ignition transformer 60 is activated again.

When the ignition transformer 60 is activated, step 120
At step 122, pre-purging is performed for a set time to establish a fuel ignition system, and at step 122, the fuel pump 28 is activated to begin supplying fuel. Further, in step 124, the needle valve actuating motor 52 is activated to move the needle portion 36 of the valve body 34 in a direction approaching the small diameter fuel passage 20.

The fuel supplied from the fuel pump 28 flows from the fuel pipe 26 through the inlet passage 24 and then into the small diameter fuel passage 20.
The fuel is fed to the nozzle hole 18 and injected, and a portion is returned from the large-diameter fuel path 22 via the return path 30. Further, the air sent from the fan 68 is sent from the opening 46 toward the nozzle hole 18 . When the valve body 34 moves in the direction of the small diameter fuel passage 20 in step 124, the small diameter fuel passage 1 is moved by the needle portion.
The effective opening area of 12 is reduced. Therefore, the fuel is supplied from the supply path 24 and is fed from the large diameter fuel path 22 to the return path 3.
The amount of fuel returned through zero decreases, and the amount of combustion fuel injected from the nozzle holes 18 increases accordingly. Therefore, the fuel spray pressure increases and the fuel is easily atomized, improving the ignitability.

After the valve body 34 is activated, it is determined in step 126 whether or not ignition has occurred (flame has been detected). If no flame is detected, the process proceeds to step 128, where it is determined whether a preset ignition trial time is in progress. If the ignition trial time is in progress, go to step 126 again.
The state of ignition is determined.

In step 126 and step 128,
If the ignition does not occur even after the ignition trial, the process proceeds to step 130 and the ignition tunnel 60 is stopped. Furthermore, the fuel pump 28 is stopped in step 132, and an alarm is issued in step 134, and the process ends.

On the other hand, if flame is detected in step 126, the process advances to step 136, where it is determined whether the post-ignition time has elapsed. If the post-ignition time is not in progress, it enters a standby state and waits for the post-ignition to complete. Once the post-ignition time has elapsed, the ignition transformer 60 is stopped in step 138.

If the ignition transformer 60 stops, step 140
Then, it is determined whether or not flame has been detected. If a flame is detected (if combustion continues), the process proceeds to step 142, and after a flag is set, the burner temperature T is measured by the thermistor 82 in step 146.

Furthermore, in step 146, this measured temperature T is compared with the set temperature _T0 . Measured temperature T is set temperature
If it is lower than T ₀ , the process proceeds to step 148 , where the needle valve operating motor 52 is driven to move the valve body 34 in a direction approaching the small diameter fuel passage 20 . Therefore, the amount of fuel that was being returned from the small diameter fuel path 20 to the fuel tank 33 via the large diameter fuel path 22 decreases, and the amount of fuel injected from the hole 18 increases. Also, step 14
If the measured temperature T is higher than the set temperature T ₀ at step 6, the process proceeds to step 150, and the valve body 34 closes the small diameter fuel passage 2.
Move in the direction away from 0. Therefore, contrary to the above, the amount of fuel returned increases and the amount of fuel injected from the nozzle holes 18 decreases. After these steps, the process returns to the stay 140 and the above-mentioned routine is repeated to keep the measured temperature T at the set temperature _T0 .
The fuel injection amount from 8 is adjusted.

On the other hand, if no flame is detected in step 140 (if the flame has been extinguished), the process advances to step 152 and it is determined whether it is the first time. If it is not the first time, the process advances to step 154, where an alarm is issued and the process ends. If it is the first time, the process proceeds to step 156, where it is determined whether the flag is set (that is, whether the flame is extinguished at the time of initial startup).

If the flag is set (that is, if the flame is extinguished under normal combustion conditions), the process advances to step 158, where the ignition transformer 60 is reactivated, and then the process returns to step 124, where a restart is attempted. on the other hand,
If the flag is not set (that is, if the flame is extinguished at startup), the process proceeds to step 160 and the fuel pump 28 is stopped. Further step 1
After the ignition transformer 60 is activated at 62, the process returns to step 120 and a similar restart is attempted.

[Effects of the Invention] As explained above, the combustion control device for a gun-type burner according to the present invention controls combustion used in a gun-type burner, in which fuel is metered by a needle valve and then injected from a nozzle for combustion. The control device includes an ignition means for igniting the fuel injected from the nozzle, a detection means for detecting whether or not combustion is in progress, and a control device for controlling the ignition means in conjunction with the operation of the ignition means when it is detected that combustion is not in progress. Since it is equipped with a moving means for moving the needle valve in a direction in which the amount of fuel injected from the nozzle increases, it has the excellent effect of being able to easily ignite the fuel regardless of whether it is at the time of starting or restarting after extinguishing the flame. are doing.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view of a gun type burner according to an embodiment of the present invention, FIG. 2 is a configuration diagram of a control device, and FIG. 3 is a flowchart showing a control routine. 10...Gun type burner, 16...Nozzle,
20...Small diameter fuel path, 22...Large diameter fuel path, 34
... Valve body, 36 ... Needle part, 52 ... Needle valve operating motor, 58 ... Ignition rod, 60 ... Ignition transformer, 66 ... Flame detector (CdS), 68 ...
…Control device.

Claims (1)

[Claims] 1. A combustion control device used in a gun-type burner that measures pressure-fed fuel using a needle valve and then injects it from a nozzle and burns it, comprising an ignition means for igniting the fuel injected from the nozzle, and a combustion control device. a detection means for detecting whether combustion is in progress; a moving means for moving the needle valve in a direction in which the amount of fuel injected from the nozzle increases in conjunction with the operation of the ignition means when it is detected that combustion is not in progress; A combustion control device for a gun-type burner.