JPH05180435A - Combustion device - Google Patents

Abstract

PURPOSE:To prevent Bunsen combustion from occurring at the initial ignition and perform a positive two-stage combustion of it. CONSTITUTION:A primary flame hole 3 is covered by a container 5 forming a primary combustion chamber 4, a secondary flame port 6 is arranged at the upper part of the container to form a combustion pipe, a temperature sensor 7 for sensing the flame temperature is arranged at the upper part of the secondary flame port of the combustion pipe, the temperature sensor 7 is cooperatively related to a fan for supplying combustion air. When the flame temperature is more than the specified temperature, it is controlled in such a way that the number of rotation of the fan is increased. At the time of ignition, since the temperature at the combustion pipe is low, so that the Bunsen combustion may easily occur. Since the flame temperature of the Bunsen combustion is higher than that under the secondary combustion, the flame temperature at this time is detected and in turn when the temperature is higher than the specified temperature, the number of rotation of the fan is increased to increase the combustion speed and the combustion is returned from the Bunsen combustion to the secondary combustion to stabilize the primary combustion and to perform the positive two-stage combustion and to accomplish the low NOx state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion device designed to reduce NOx.

[0002]

2. Description of the Related Art As a conventional combustion apparatus designed to reduce NOx, for example, as shown in Japanese Patent Publication No. 62-39329, a primary flame hole portion having a primary flame hole or a burner body. Is covered with a container forming a primary combustion chamber, and a secondary flame port having a single opening is provided on the upper surface of the container to perform a two-stage combustion bar in which primary combustion and secondary combustion are performed separately. There is na.

Such a two-stage combustion burner is separated into a primary flame and a secondary flame, and the maximum temperature and average temperature of the flame are lowered, so that the generation of NOx can be reduced.

[0004]

However, in such a conventional two-stage combustion type combustion apparatus, the temperature of the combustion tube is different between the case of initial ignition and the case of reignition.
At the time of initial ignition, the combustion speed is slow because the temperature of the air-fuel mixture in the vessel forming the combustion tube is low, and the primary flame is not formed because the flame is not held in the primary flame hole. However, there is a problem in that the Bunsen combustion state that forms a flame is likely to occur.

It is an object of the present invention to provide a combustion device that detects the flame temperature and returns to the two-stage combustion when the Bunsen combustion state is reached and surely performs the two-stage combustion even at the initial ignition.

[0006]

In order to achieve the above object, the present invention has the following constitution.

That is, the primary flame hole portion having the primary flame hole is set to 1
While covering with a container that forms the next combustion chamber, a secondary flame port is provided on the upper part of this container to form a combustion pipe, and a temperature detector for detecting the flame temperature is provided on the secondary flame port of the combustion pipe. Associate this temperature detector with a fan that supplies combustion air,
When the flame temperature is above a certain temperature, the fan speed is controlled to be high.

[0008]

Operation: At the time of initial ignition, if the Bunsen combustion state is reached without performing two-stage combustion, the flame temperature rises. This flame temperature is detected by the temperature detector and the rotation speed of the fan is increased. As a result, the amount of air is increased to bring the inside of the container closer to the theoretical amount of air, the combustion speed of the air-fuel mixture is increased, and a flame is held in the primary flame hole so as to backfire from the secondary flame hole, and the primary flame is generated. Form and eliminate Bunsen combustion. In this way, keep the fan speed high until the Bunsen combustion disappears and the flame temperature drops,
When the flame temperature drops due to the two-stage combustion, the fan speed is returned to the proper speed corresponding to the combustion amount.

[0009]

1 is a perspective view showing an embodiment of the present invention, FIG.
1 is a cross-sectional view of a main part, and 1 is a primary flame hole portion 3 having a primary flame hole 2 covered with a container 5 forming a primary combustion chamber 4,
It is a combustion tube formed by providing a secondary flame port 6 on the upper part of this container 5. Reference numeral 7 denotes a temperature detector provided above the secondary flame port 6 of the combustion pipe 1, which is associated with a fan (not shown) for supplying combustion air. When the flame temperature is equal to or higher than a certain temperature, the fan rotation speed is changed. Control to make it higher. 8 is a mixing part.

Next, the control operation of this combustion apparatus will be described with reference to the flow chart of FIG.
Explain by chart. At the time of combustion, when ignition is performed in step 10, the process proceeds to step 11, and the temperature detector 7 detects the flame temperature, and if the temperature is below a certain temperature, the combustion is normally performed in two stages. Steady combustion is performed by controlling to an appropriate rotation speed. If the flame temperature is equal to or higher than the constant temperature in step 11, the process proceeds to step 13 to increase the fan rotation speed by a constant value or more to increase the air amount compared to the steady state, and bring the air amount in the container 5 closer to the theoretical air amount. Control is performed to increase the combustion speed, and the procedure returns to step 11 to detect the flame temperature, and the primary flame detects the primary flame hole 2
Then, if it is confirmed that the flame temperature has dropped below a certain temperature by holding the secondary flame port 6 so as to backfire and canceling the Bunsen combustion, the process proceeds to step 12 and the fan is returned to the proper rotational speed. If the flame temperature is equal to or higher than the predetermined temperature in step 11, the fan rotation speed is kept high in step 13. Then, the flame temperature detection in step 11 is repeated and the fan rotation speed is kept high until the flame temperature decreases, and when the flame temperature decreases, the process proceeds to step 12 to return the fan to the proper rotation speed.

Normally, in the two-stage combustion burner, the inside of the container 5 is burned in a state of less than the theoretical air amount, and the unburned portion is burned at the secondary flame port 6, so that the primary flame is stabilized. The sex is low. When the air-fuel ratio of the air-fuel mixture in the container 5 is determined so that the primary flame is held in the primary flame holes 2 in a state where the temperature of the container 5 rises due to combustion, the mixture in the container 5 is mixed at the cold start. Since the combustion speed of air is low, the primary flame does not hold in the primary flame hole 2. So, at the time of this cold start,
When the Bunsen combustion state occurs when the primary flame is not formed and only the secondary flame mouth 6 is formed and the Bunsen combustion state is reached, the flame temperature rises. Therefore, this flame temperature is detected and the flame temperature is kept constant. When it is higher than the above, the amount of air in the container 5 is increased more than that in the steady state, the combustion velocity is increased by approaching the theoretical amount of air, and the flame is fired in the primary flame hole 2 by backfire from the secondary flame port 6. Then, the Bunsen combustion is restored to the two-stage combustion. Since the flame temperature is lowered when the combustion returns to the two-stage combustion, the fan is returned to the proper rotation speed and the steady combustion is performed when the flame temperature is detected.

[0012]

As described above, the present invention pays attention to the difference in flame temperature between the normal two-stage combustion and the Bunsen combustion state, detects the flame temperature, and when the flame temperature is higher than a certain temperature by the Bunsen combustion. Causes the primary flame to be formed by increasing the fan rotation speed and temporarily increasing the combustion speed to backfire to the primary flame hole, so be sure to return it to the two-stage combustion if the Bunsen combustion state is reached. Therefore, low NOx can be achieved.

[Brief description of drawings]

FIG. 1 is a perspective view of a combustion apparatus showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the main parts of the combustion device of the present invention.

FIG. 3 is a flowchart showing a control operation.

[Explanation of symbols]

 1 Combustion device 2 Primary flame hole 3 Primary flame hole part 4 Primary combustion chamber 5 Container 6 Secondary flame port 7 Temperature detector

Front page continuation (72) Inventor Satoshi Kawaguchi, Noritsu Co., Ltd., 32 Akashi-cho, Chuo-ku, Kobe-shi, Hyogo Prefecture (72) Inventor Hideo Ueda 32 Akashi-cho, Chuo-ku, Kobe, Hyogo, Ltd.

Claims (1)

[Claims] 1. A primary flame hole portion having a primary flame hole is covered with a container forming a primary combustion chamber, and 2 is provided on the upper part of this container.
A secondary flame port is provided to form a combustion tube, and a temperature detector for detecting the flame temperature is provided above the secondary flame port of the combustion tube, and this temperature sensor is associated with a fan for supplying combustion air. When the temperature is higher than a certain temperature, the combustion device is controlled so as to increase the fan rotation speed.