JP2009228942A - Stirring blade for mixing gas - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stirring blade for mixing gases can quickly stir and mix gases in an exhaust gas duct to which two or more kinds of gases are introduced, and be easily manufactured as it has a simple structure. <P>SOLUTION: This stirring blade disposed in the exhaust gas duct to which two or more kinds of gases are introduced to mix the gases, is composed of a set of two sheets of rectangular plate bodies 2, 2 mounted on a shaft 12 orthogonally to the longitudinal direction at a center of the duct 10, and two sheets of rectangular plate bodies 2, 2 are mounted in a state that they are intersected with each other on the shaft in a side view of the duct, and obliquely twisted in the same direction to the longitudinal direction in a plane view of the duct. An projection area to the duct cross-sectional direction of the intersected two sheets of rectangular plate bodies 2, 2 is preferably within a range of 15-30% to a cross-sectional area of the duct 10. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a gas mixing stirring blade that can quickly stir and mix gases in an exhaust gas duct into which two or more kinds of gases are introduced, and that can be easily manufactured with a simple structure.

  In the periphery of the kiln, a large-diameter exhaust gas duct having a diameter of about 2 m is installed. However, these exhaust gas ducts are usually made of steel pipes from the viewpoint of cost. However, if the steel pipe is heated to 350 ° C or higher, the oxidation reaction becomes active, causing corrosion and peeling, and the life of the duct is shortened. Therefore, cooling air (about 30 ° C) is simultaneously supplied into the duct. The high temperature gas of about 1200 ° C. is cooled.

  On the other hand, when performing temperature management of the entire kiln, heat balance calculation of energy loss, or the like, it is assumed that the average temperature of the entire gas flowing in the exhaust gas duct is grasped. However, as described above, the temperature distribution and velocity distribution of the fluid in the large-diameter duct immediately after mixing the high-temperature gas and the low-temperature gas are not easy because the high-temperature gas tends to flow in the upper part and the low-temperature gas tends to flow in the lower part. It is uniform. For this reason, when the temperature was measured with a thermocouple, a part of the non-uniform flow rate was measured, and the temperature of the entire flow rate could not be grasped.

  In addition, as shown in the graph of FIG. 7, the result of measuring the temperature deviation value with respect to the flow velocity of gas flowing in a duct having a pipe diameter of 2 m (range of 5 to 20 m / s) is 600 when the flow velocity is 5 m / s. After that, although the temperature deviation value becomes smaller in inverse proportion to the flow rate, the temperature deviation value is still as high as 400 ° C even when the flow rate becomes as high as 20 m / s, and the uniform stirring and mixing of the gas flow is sufficient. It has been confirmed that this has not been done.

Therefore, as a method for stirring and mixing the entire gas, a method of mixing the gas by installing an orifice in the duct was generally used. For example, when the flow rate is 20 m / s, the pressure loss is extremely high from 500 Pa to 1000 Pa. Large and inefficient. Further, a damper is installed in the pipe, and a method of mixing exhaust gas and cooling air while controlling the opening degree of the damper (see, for example, Patent Document 1), and further, a screw-shaped stirring blade in the duct However, the production of dampers and large-diameter screws is enormous in cost, requires a long production time, and is actually difficult to install in all exhaust gas ducts. there were.
JP 2006-52920 A

  The present invention solves the above-mentioned problems, can quickly stir and mix the gas in the exhaust gas duct into which two or more kinds of gases are introduced, and is easy to manufacture and attach to the duct. Furthermore, the present invention has been completed for the purpose of providing a gas mixing stirring blade that can be manufactured at low cost.

  The gas mixing stirring blade of the present invention made to solve the above problems is a gas mixing stirring blade that is installed in an exhaust gas duct into which two or more gases are introduced and mixes the gas. In the state where the two rectangular plates are attached to each other on a shaft installed so as to be orthogonal to the longitudinal direction at the center of each other, and the two rectangular plates are crossed with respect to each other about the shaft in a side view of the duct. And it is attached in the state twisted diagonally in the same direction with respect to the longitudinal direction in a plan view of the duct.

The projected area of the two crossed rectangular plates in the duct cross-sectional direction is preferably in the range of 15 to 30% with respect to the cross-sectional area of the duct.
Furthermore, it is preferable that the inclination angle of the two rectangular plates in plan view is in the range of 30 to 60 ° with respect to the longitudinal direction of the duct, and this is the invention according to claim 3.

  The stirring blade for gas mixing of the present invention is composed of a set of two rectangular plates that are mounted on a shaft that is installed so as to be orthogonal to the longitudinal direction at the center of the duct, and these two rectangular plates are viewed from the side of the duct. In the state of crossing each other with the axis as the center, and in a plan view of the duct, it is attached in a state of being twisted obliquely in the same direction with respect to the longitudinal direction. It turns downward while being twisted, and after hitting the inner wall of the duct, it flows again toward the center. On the other hand, the gas flowing in the lower part of the duct is upward and turns upward while being twisted diagonally. After hitting the inner wall of the duct, it flows again toward the center, and is uniform with the gas flow in a short time. To be stirred and mixed.

  In the invention according to claim 2, the projected area of the two crossed rectangular plates in the duct cross-sectional direction is in the range of 15 to 30% with respect to the cross-sectional area of the duct. It can be stirred and mixed, and there is no pressure loss in the gas stream.

  Furthermore, in the invention according to claim 3, since the inclination angle of the two rectangular plates in a plan view is in the range of 30 to 60 ° with respect to the longitudinal direction of the duct, the gas flow is along the rectangular plates. The flow is changed in an oblique direction with respect to the longitudinal direction of the body, and uniform stirring and mixing is realized.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
The drawings show an example in which the gas mixing stirring blades of the present invention are installed in an exhaust gas duct. FIG. 1 is a side view showing the outline, FIG. 2 is a plan view showing the outline, and FIG. 3 is a front view showing the outline. FIG. In the figure, reference numeral 10 denotes an exhaust gas duct, and two gases of high temperature (about 1200 ° C.) exhaust gas and cooling air (about 30 ° C.) are introduced into the duct 10. Further, a stirring blade 1 for gas mixing is installed downstream from the place where these two gases merge by a distance approximately corresponding to the duct tube diameter.

  The stirring blade 1 is composed of a set of two rectangular plates 2 and 2. The rectangular plate 2 is made of heat resistant steel such as SUS304. In addition, the rectangular plate 2 is attached to a shaft 12 that is installed so as to be orthogonal to the longitudinal direction via a bracket 11 at the center of the duct 10, and the rectangular plate 2 is further viewed in a side view of the duct. They are attached in a state of crossing each other around the axis (see FIG. 1) and in a state of being twisted obliquely in the same direction with respect to the longitudinal direction in a plan view of the duct (see FIG. 2).

That is, one of the two rectangular plates 2 and 2 in a state of crossing each other around the shaft 12 in a side view of the duct 10 changes the direction of the hot gas flowing in the upper part to the lower part. On the other hand, the other is to change the direction of the low-temperature gas flowing in the lower part upward. In addition, uniform stirring and mixing cannot be performed by simply changing the gas flow up and down as described above. Therefore, in the present invention, the duct 10 is further twisted obliquely in the same direction with respect to the longitudinal direction in plan view.
As a result, the hot gas flowing in the upper part of the duct turns downward and turns downward while being twisted diagonally, and after hitting the inner wall of the duct, it is reflected and flows toward the center again. On the other hand, the low-temperature gas flowing in the lower part of the duct turns upward and turns upward while being twisted obliquely, and after hitting the inner wall of the duct, it is reflected and flows toward the center again.

  As a result, the two types of gas flows are stirred while being automatically swirled downstream of the stirring blade 1 in the duct, so that they are uniformly mixed in an extremely short time, and the temperature deviation of the gas flow is almost eliminated. It becomes. For this reason, it becomes possible to grasp | ascertain the temperature of the whole uniform flow velocity irrespective of where it is downstream from the said stirring blade 1.

Thus, in order to uniformly stir and mix the two types of gas flows, the projected area of the two crossed rectangular plates 2 and 2 in the duct cross-sectional direction is 15 to 30% with respect to the cross-sectional area of the duct. It is preferable to design so that it exists in the range.
This is because if the two rectangular plates 2 and 2 are set up vertically so as to obstruct the gas flow, the stirring force increases, but the resistance increases, and conversely if they are laid down horizontally. Although the resistance is reduced, the stirring force is reduced, so that the projected area in the duct cross-sectional direction from the empirically designed value is in the range of 15-30% with respect to the cross-sectional area of the duct. In addition, what is necessary is just to adjust the angle of the rectangular board 2 in the range of about +/- 25 degrees on the basis of 45 degrees for field work. In the illustrated embodiment, it is inclined at 45 °.

Moreover, it is preferable to design so that the inclination angle of the two rectangular plates 2 and 2 in a plan view is in a range of 15 to 60 ° with respect to the longitudinal direction of the duct.
This is because uniform stirring and mixing cannot be performed by simply crossing the two rectangular plates 2 and 2 in the vertical direction. If the angle of inclination is less than 15 °, it is difficult to impart a sufficient twist to the gas flow in an oblique direction, and if it is greater than 60 °, the rectangular plate 2 may hit the tube wall of the duct 10. Range. In addition, it is easy and easy to set what is inclined at 45 ° for field work.

In the embodiment, as shown in FIG. 4, the rectangular plate body 2 has a plate body portion 3 and a reinforcing portion 4 joined in a T-shaped cross section. Has a structure in which an elliptical cutout portion 5 is formed.
Such a rectangular plate 2 can be accurately manufactured in a short time as long as there is a metal plate piece. Moreover, as shown in FIG. 5, the attachment to the shaft 12 is related to the elliptical notch 5. Since it is only welded after being adjusted to a predetermined angle, it can be easily mounted even by a skilled worker.

  Using the stirring blade described above, the temperature deviation value with respect to the flow velocity of gas flowing in the duct having a pipe diameter of 2 m (range of 5 to 25 m / s) was measured. As a result, as shown in the graph of FIG. 6, it was 50 to 75 ° C., and it was confirmed that the temperature of the entire gas flow rate could be accurately measured by the thermocouple. In addition, it was confirmed that the pressure loss when the flow rate was 20 m / s was as low as 50 to 100 Pa, and an efficient temperature measurement was possible.

  As is clear from the above description, the gas mixing stirring blade of the present invention is composed of a set of two rectangular plates attached on a shaft constructed so as to be orthogonal to the longitudinal direction at the center of the duct. Two rectangular plates are attached in a state of crossing each other around the axis in a side view of the duct and twisted in the same direction with respect to the longitudinal direction in a plan view of the duct. The gas in the exhaust gas duct into which the above gas is introduced can be quickly and uniformly stirred and mixed, and can be easily manufactured and attached to the duct with a simple structure. In addition, since the agitation and mixing is performed in a short time, the apparatus can be made compact with a short duct, and the number of places to be lined with stainless steel for heat resistance can be reduced and the cost can be reduced. There is also an advantage.

It is a side view which shows embodiment of this invention. It is a top view which shows embodiment of this invention. It is a front view which shows embodiment of this invention. It is a perspective view which shows the rectangular plate body of this invention. It is a perspective view which shows the stirring blade of this invention. It is a graph which shows the relationship between the gas flow velocity in this invention, and the temperature deviation in a duct. It is a graph which shows the relationship between the gas flow velocity and the temperature deviation in a duct in a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Stirring blade 2 Rectangular plate 3 Plate body part 4 Reinforcement part 5 Notch part 10 Duct 11 Bracket 12 Axis

Claims (3)

  A gas mixing stirring blade that is installed in an exhaust gas duct into which two or more kinds of gases are introduced and mixes the gases, and is installed on a shaft that is installed perpendicularly to the longitudinal direction at the center of the duct. It consists of a pair of rectangular plates, and these two rectangular plates are crossed with respect to each other about the axis in a side view of the duct, and twisted obliquely in the same direction with respect to the longitudinal direction in a plan view of the duct The stirring blade for gas mixing characterized by being attached by.   2. The gas mixing stirring blade according to claim 1, wherein a projected area of two crossed rectangular plates in a duct cross-sectional direction is in a range of 15 to 30% with respect to a cross-sectional area of the duct.   The stirring blade for gas mixing according to claim 1, wherein an inclination angle of the two rectangular plates in a plan view is in a range of 30 to 60 ° with respect to a longitudinal direction of the duct.

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