JPS6363814B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an air register for an after-air port that can freely adjust the swirling direction and swirling speed of combustion air.

Nitrogen oxides (hereinafter referred to as nitrogen oxides) are one of the air pollutants.
The following methods have been adopted in combustion devices such as boilers to reduce NOx (referred to as NOx). These include (1) the two-stage combustion method, (2) the use of low NOx burners, and (3) the mixing of exhaust gas, and more recently, the use of incomplete combustion in certain burners and the reduction effect of the resulting intermediate products. A method of reducing NOx has also been adopted. However, all of these methods cause incomplete combustion when viewed from the viewpoint of combustion, and the combustion efficiency decreases. For this reason, during low NOx operation, efforts are usually made to reduce NOx while also improving combustion efficiency by combining several of the above methods.

For example, even in the two-stage combustion method, in addition to performing low-oxygen combustion in the first stage combustion, methods such as introducing exhaust gas to lower the flame temperature are often used in combination. In this case, as a matter of course, a considerable amount of unburned matter such as carbon is generated in the first stage combustion. Therefore, as a second stage, secondary air is introduced downstream of the first stage combustion section to combust the unburned matter. For this purpose, an opening is provided in the furnace wall to supply secondary air to the wake of the combustion gas flow from the first stage combustion section, and the secondary air from this opening is allowed to flow into the furnace to remove unburned matter in the combustion gas. It's burning. (This opening is referred to as an after-air port.) Conventionally, no special consideration has been given to the device installed in this opening to enhance the input of secondary air throughflow into the furnace in response to the combustion load.

In addition, in recent low NOx combustion methods, an air ratio
A burner (auxiliary burner) with a low air ratio of 0.6 etc. is installed,
A method is employed to remove NOx from the combustion gas by using reducing intermediate products generated by the auxiliary burner.

Also in this case, since a low air ratio burner is used, there are many unburned components in the exhaust gas, and it is necessary to provide the above-mentioned after-air port and supply secondary air to sufficiently burn the unburned components. .

On the other hand, ordinary burners and low air ratio burners are built integrally with the burner and supply secondary air from around the burner to surround the burner flame to improve mixing with the fuel and ensure good combustion even when the combustion load changes. A burner structure with fixed blades is adopted.

(For example, the invention of JP-A-53-145130,
(Invention of Publication No. 13017) However, since all of these use fixed swirling vanes as a means for imparting swirling force to the secondary air, an appropriate combustion state is created for the amount of fuel that corresponds to changes in the boiler load. However, sufficient ejection energy and swirling energy are not given to the secondary air, and the combustion rate of unburned matter decreases compared to the amount of supplied air, and soot and unburned matter increase.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned problems of the prior art and to provide an air register for an after-air port in which the swirling force and direction of combustion air can be freely adjusted.

In short, this invention has a configuration in which a plurality of blades are formed on the side wall of an air register main body for an after air port formed in a substantially cylindrical shape, and the inclination angle and direction of each of these blades can be freely changed by a link mechanism. It is.

Embodiments of the present invention will be described below with reference to the accompanying drawings.

In FIG. 1, the air inlet portion 1a of the air register body 1 is formed in a cylindrical shape, and the end portion of the air register body 1 on the furnace 2 side is narrowed into a substantially trapezoidal shape to form a nozzle portion 1b. A plurality of blades 3 are attached to the cylindrical air inflow portion 1a so as to form part of the cylindrical side wall when the air inflow portion 1a is in a fully closed state. As shown in FIG. 3, this blade 3 is swingably attached to a frame 1a' of the air inflow section 1a by a rotating shaft 4. A swing arm 5 is formed on each rotating shaft 4, and a link bar 6 is hinged to the lower end of the swing arm 5. The link bar 6 interconnects adjacent swing arms 5 and is generally formed in an annular shape on the inner surface of the air register body 1 as shown in FIG. As shown in FIG. 4, a swing arm 7 for swinging the swing bar is attached to the swing bar 5a, which is one of the link mechanisms described above.
This swing arm 7 swings the swing bar 5 via an operating rod 8 and an intervening arm 9 that can be operated from outside the wind box in which the air register is arranged. For example, actuating rod 8
When pulled in the X direction, this force is transmitted to the swing bar 5a via the intervening arm 9 and the swing arm 7, and the swing bar 5a swings in the Z direction. As the swing bar 5a swings, the blade 3 tilts to the 3' position. The swinging motion of the swing bar 5a is transmitted to each swing bar 5 via each link bar 6, causing each blade 3 to tilt. Conversely, if the actuating rod 8 is pushed in the Y direction, it will tilt in the opposite direction.

With the above configuration, the operator can set the inclination angle and direction of the blade 3 in accordance with the combustion air flow rate by operating the actuating rod 8 in the X or Y direction, and set the swirling force and direction of the combustion air. Adjust.

Furthermore, the first stage burner (usually the main burner) used in the two-stage combustion is provided with an air register, and this register improves the mixing of the fuel and the secondary air for the burner. Therefore, the flame of the first stage burner is swirling, and the secondary air from the after-air port, which aims to burn the unburned components in the combustion gas, has a swirl in a direction that suppresses the rise in the swirl, and the unburnt components are sufficiently removed. It is necessary to measure the combustion of

Further, in a large boiler, the after air ports are arranged on opposing wall surfaces, respectively, facing each other or not facing each other.

Therefore, for example, the direction of rotation of the opposing after-air ports must be selected and arranged so as to improve the residence time of the combustion gas in the furnace and to achieve complete combustion from the viewpoint of mixing with the combustion gas.

For this reason, air registers for after-airports of the same type are manufactured, and during operation, the after-airport turning direction can be adjusted for each arrangement, such as changing from left-hand turn to right-hand turn.

By implementing this invention, the swirling force and swirling direction of the combustion air can be freely set, so that the combustion air can be mixed well and the combustion efficiency can be increased. Particularly when performing low NOx combustion, by arranging this air register at the after-air port, unburned matter can be effectively combusted.

[Brief explanation of drawings]

Fig. 1 is a sectional view of the air port section showing the state in which the air register according to the present invention is attached to the air port, Fig. 2 is a sectional view taken along line A-A in Fig. 1, and Fig. 3 is a partial plan view of the air register. , FIG. 4 is an enlarged partial view of FIG. 1...Air register body, 3...Blade, 5...
Swing arm, 6...link arm, 7...swing arm.

Claims (1)

[Claims] 1. In a device that supplies secondary air for an after-air port to completely burn unburned components in burner combustion exhaust gas, a plurality of blades are attached to the side wall of an air register formed in a substantially cylindrical shape. It is characterized by being rotatably mounted around a shaft, and configured so that the inclination angle and direction of each of these blades can be freely set using a link mechanism, thereby making the swirling direction of the secondary air from the air port variable. Air register with variable rotation direction for air ports. 2. The link mechanism is composed of a swing arm attached to each blade, a link bar interposed between each adjacent swing arm and hinged, and furthermore, one of the swing arms of the swing arm is attached to the outside. 2. The variable turning direction air register for an air port according to claim 1, wherein the air register is configured to swing due to a force from the air register.