JP3965516B2 - Paddle stirring powder heating device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a paddle stirring type powder heating apparatus, for example, a paddle stirring type powder heating apparatus used for thermal decomposition treatment of dioxins applied to incineration fly ash discharged by incineration processing of municipal waste or industrial waste. About.
[0002]
[Prior art]
Conventionally, as a paddle stirring type powder heating device, a horizontal cylindrical heating tank closed at both ends, a rotating shaft arranged so as to be coaxial with the heating tank, and an outer peripheral surface of the rotating shaft A stirring paddle made of a rigid body provided in a fixed shape and a heating source disposed on the entire outer periphery of the peripheral wall of the heating tank are known.
[0003]
In this heating device, the heat generated from the heating source is transmitted to the powder in the tank through the peripheral wall of the heating tank, whereby the powder is heated. Therefore, the stirring paddle efficiently stirs and mixes the powder heated in the vicinity of the inner peripheral surface of the peripheral wall of the heating tank and the powder in the other part for the purpose of uniformly heating the entire powder. There is a need to be able to do it. In order to meet such a requirement, it is preferable to bring the tip of the stirring paddle as close as possible to the inner peripheral surface of the heating tank, and it is desirable to make it contact.
[0004]
[Problems to be solved by the invention]
However, in the conventional paddle stirring type powder heating apparatus, the stirring paddle is made of a rigid body and is fixed to the rotating shaft, so in practice, there are several between the tip of the stirring paddle and the inner peripheral surface of the heating tank. Manufactured and operated with a gap of mm to several tens of mm. Therefore, there exists a powder immovable layer that is not agitated by the agitation paddle along the inner peripheral surface of the heating tank. As a result of the existence of such a immobile layer, the following problems occur.
[0005]
That is, the non-moving layer of the powder functions as a heat insulating layer, and the heating efficiency of the powder in the tank through the peripheral wall of the heating tank due to the heat generated from the heating source is lowered. In order to solve such a problem, it is necessary to increase the amount of heat generated from the heating source, or to enlarge the heating tank to increase the residence time of the powder in the tank. Get higher. In addition, depending on the type of powder, there is a powder that partially or wholly melts when heated to a predetermined temperature or higher. When the amount of heat generated by the heating source is increased, the powder is sintered in the immobile layer. As a result, friction between the tip of the stirring paddle and the non-moving layer increases, and abnormal noise is generated, and the stirring paddle is worn or damaged.
[0006]
An object of the present invention is to provide a paddle stirring type powder heating apparatus capable of solving the above-mentioned problems and preventing the generation of a powder immobile layer along the inner peripheral surface of the peripheral wall of a heating tank.
[0007]
[Means for Solving the Problems and Effects of the Invention]
A paddle stirring type powder heating apparatus according to the invention of claim 1 includes a horizontal cylindrical heating tank closed at both ends, a rotating shaft rotatably disposed so as to be coaxial with the heating tank, and a rotating shaft. A paddle stirring type powder heating apparatus provided with a stirring paddle provided on an outer peripheral surface of a shaft and a heating source disposed around a peripheral wall of a heating tank, wherein a plurality of arms are radially provided on the outer peripheral surface of a rotating shaft. The stirring paddle is pivotally attached to the tip of each arm, and the position of each stirring paddle in contact with the inner peripheral surface of the heating tank and the inner wall of the heating tank It is made to oscillate around an axis parallel to the rotation center axis of the rotary shaft between a position away from the peripheral surface, and by this oscillation, the tip of each stirring paddle is rotated during one rotation of the rotary shaft. The part should touch at least a part of the entire inner peripheral surface of the heating tank. In which, at the same position with respect to the length direction of the rotary shaft, in which a plurality of stirring paddles rotating shaft are out of contact position to the heating tank circumferential surface of the distal end portion during one rotation is provided is there.
[0008]
According to the paddle stirring type powder heating apparatus of the first aspect of the present invention, a plurality of arms are provided radially and fixedly on the outer peripheral surface of the rotating shaft, and a stirring paddle is pivotally attached to the tip of each arm. Each stirring paddle has an axis parallel to the rotation center axis of the rotating shaft between a position where the tip thereof contacts the inner peripheral surface of the peripheral wall of the heating tank and a position separated from the inner peripheral surface of the peripheral wall of the heating tank. The tip of each stirring paddle is in contact with at least a part of the entire inner peripheral surface of the peripheral wall of the heating tank while the rotation shaft makes one rotation. In the portion where the tip portion is in contact with the inner peripheral surface of the peripheral wall of the heating tank, a powder immobile layer is not formed. Therefore, a reduction in heating efficiency of the powder in the tank through the peripheral wall of the heating tank due to heat generated from the heating source is prevented. As a result, it is not necessary to increase the amount of heat generated from the heating source or to enlarge the heating tank so as to increase the residence time of the powder in the tank, thereby reducing the cost. Further, since the formation of the non-moving layer is prevented, the sintering of the powder in the non-moving layer can be prevented, and the generation of abnormal noise and the abrasion or breakage of the stirring paddle can be prevented.
[0009]
In addition, a plurality of agitation paddles are provided at the same position in the length direction of the rotating shaft so that the contact position of the tip portion with the inner peripheral surface of the heating tank during one rotation of the rotating shaft is shifted. In the same position with respect to the length direction of the shaft, the formation of a non-moving layer is prevented over a wide range of the inner peripheral surface of the peripheral wall of the heating tank .
[0010]
The paddle stirring type powder heating apparatus according to the invention of claim 2 is such that, in the invention of claim 1, the stirring paddle is swung by its own weight. In this case, a separate means for swinging the stirring paddle is not required.
[0011]
The paddle stirring type powder heating apparatus according to the invention of claim 3 is the invention according to claim 1 or 2, wherein the contact position of the tip of the stirring paddle with the inner peripheral surface of the heating tank is a pivoted position on the arm of the stirring paddle When the distance between the pivot location and the mixing paddle tip, is what is done as determined by the position of the center of gravity of the stirring paddle.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. In the following description, based on the rotation direction of the rotation shaft (see arrows in FIGS. 1 to 4), the front of the rotation direction is referred to as the front, and the opposite side is referred to as the rear.
[0013]
FIG. 1 shows a cross section of a paddle stirring type powder heating apparatus according to the present invention, and FIGS. 2 to 4 show the operation of each stirring paddle provided at the same position in the longitudinal direction of the rotating shaft.
[0014]
In FIG. 1, a paddle stirring type powder heating apparatus includes a horizontal cylindrical heating tank (1) closed at both ends, and a rotation arranged in the heating tank (1) so as to be coaxial with the rotation. A plurality of, in this case, three stirring paddles (3), (4), (5) provided at a plurality of positions spaced apart in the longitudinal direction on the outer peripheral surface of the shaft (2) and the rotating shaft (2) And a heating source (not shown) made of an electric heater or the like disposed around the peripheral wall (1a) of the heating tank (1). The heating tank (1) is arranged in an inclined manner so that one end is located above the other end, and the powder formed on the upper part of one end of the peripheral wall (1a) of the heating tank (1) The powder (P) charged from the charging port is discharged from a powder discharging port formed in the lower part of the other end. The rotating shaft (2) is rotationally driven by a driving source (not shown).
[0015]
A plurality of, in this case, three arms (6), (7), (8) are radially spaced at the same position in the longitudinal direction of the rotating shaft (2) on the outer peripheral surface of the rotating shaft (2). The first to third stirring paddles (3), (4) and (5) are pivotally attached to the tips of all the arms (6), (7) and (8), respectively. Yes. The first to third stirring paddles (3), (4), and (5) are in the form of strips having a predetermined length in a direction orthogonal to the paper surface of FIG. 1, and are parallel to the rotation center axis of the rotation shaft (2). It is pivotally attached to the arms (6), (7) and (8) by the pin (9), so that it swings around the axis of the pin (9).
[0016]
As shown in FIG. 2, a weight (11) having a predetermined weight is attached to the first stirring paddle (3) at a predetermined position, and the center of gravity (G1) of the first stirring paddle (3) is attached by the weight (11). ) Is located in front of the pin (9), and passes through the central axis of the pin (9) when the rotation angle of the arm (6) is 90 degrees and 270 degrees from the top vertically (see FIGS. 2A1 and 2). It is located on the vertical plane (V1), and when it is within the range of more than 90 degrees and less than 270 degrees (see Fig. 2A3), the vertical plane passing through the central axis of the pin (9) is also forward (V1) It is made to be located in. As a result, when the rotation angle of the arm (6) is 90 degrees and 270 degrees from vertically above, no rotational force acts on the first stirring paddle (3), but it also exceeds 90 degrees and less than 270 degrees. 2, the counterclockwise rotational force in FIG. 2 acts by its own weight. This rotational force is minimum when the rotation angle of the arm (6) is in the vicinity of 90 degrees from vertically above, gradually increases as the rotation angle increases, reaches a maximum at 180 degrees, and further exceeds 180 degrees. It gradually decreases and becomes a minimum in the vicinity of 270 degrees. The distance between the central axis of the pin (9) and the leading edge of the first stirring paddle (3) is determined by the distance between the central axis of the pin (9) and the inner peripheral surface of the peripheral wall (1a) of the heating tank (1). Moreover, the front edge of the first stirring paddle (3) is in contact with the inner peripheral surface of the peripheral wall (1a) of the heating tank (1) when the rotation angle of the arm (6) is 90 degrees and 270 degrees from vertically above It is made to do. Therefore, when the rotation angle of the arm (6) is in the range of 90 to 270 degrees from vertically above, the leading edge of the first stirring paddle (3) contacts the inner peripheral surface of the peripheral wall (1a) of the heating tank (1). However, it does not contact within the range of more than 270 degrees and less than 90 degrees. In particular, when the rotation angle of the arm (6) exceeds 90 degrees vertically and less than 270 degrees, the leading edge of the first stirring paddle (3) is heated by a predetermined force by the rotational force acting on the first stirring paddle (3). It is pressed against the inner peripheral surface of the peripheral wall (1a) of (1). This pressing force is proportional to the rotational force. In addition, at the rear edge of the first stirring paddle (3), when the rotation angle of the arm (6) exceeds 270 from below and is less than 90 degrees, the first stirring paddle (3) in FIG. A stopper portion (3a) is provided for preventing an excessive swing in the direction.
[0017]
As shown in FIG. 3, a weight (12) having a predetermined weight is attached to the second stirring paddle (4) at a predetermined position, and the center of gravity (G2) of the second stirring paddle (4) is attached by the weight (12). ) Is located in front of the pin (9), and passes through the central axis of the pin (9) when the rotation angle of the arm (7) is 45 degrees and 225 degrees from the top (see FIGS. 3B1 and B2). It is located on the vertical plane (V2), and when it is in the range of more than 45 degrees and less than 225 degrees (see Fig. 3B3), it is ahead of the vertical plane (V2) passing through the central axis of the pin (9) It is made to be located. As a result, when the rotation angle of the arm (7) is 45 degrees and 225 degrees from the top vertically, no rotational force acts on the second stirring paddle (4), but it also exceeds 45 degrees and less than 225 degrees. In some cases, the counterclockwise rotational force of FIG. 3 acts by its own weight. This rotational force is minimum when the rotation angle of the arm (7) is around 45 degrees from above vertically, gradually increases as the rotation angle increases, reaches its maximum at 135 degrees, and further exceeds 135 degrees. It gradually decreases and becomes a minimum in the vicinity of 225 degrees. The distance between the center axis of the pin (9) and the front edge of the second stirring paddle (4) is determined by the distance between the center axis of the pin (9) and the inner peripheral surface of the peripheral wall (1a) of the heating tank (1). Moreover, the front edge of the second stirring paddle (4) is in contact with the inner peripheral surface of the peripheral wall (1a) of the heating tank (1) when the rotation angle of the arm (7) is 45 degrees and 225 degrees from vertically above It is made to do. Therefore, when the rotation angle of the arm (7) is within the range of 45 to 225 degrees from the vertical upper side, the leading edge of the second stirring paddle (4) contacts the inner peripheral surface of the peripheral wall (1a) of the heating tank (1). However, it does not contact within the range of more than 225 degrees and less than 45 degrees. In particular, when the rotation angle of the arm (7) exceeds 45 degrees vertically and less than 225 degrees, the leading edge of the second agitation paddle (4) is heated by a predetermined force due to the rotational force acting on it. It is pressed against the inner peripheral surface of the peripheral wall (1a) of (1). This pressing force is proportional to the rotational force. In addition, at the rear edge of the second stirring paddle (4), when the rotation angle of the arm (7) is more than 225 degrees and less than 45 degrees from vertically above, FIG. A stopper portion (4a) is provided for preventing excessive clockwise rotation.
[0018]
As shown in FIG. 4, a weight (13) having a predetermined weight is attached at a predetermined position to the third stirring paddle (5), and the center of gravity (G3) of the third stirring paddle (5) is attached by the weight (13). ) Is located in front of the pin (9), and passes through the central axis of the pin (9) when the angle of rotation of the arm (8) is 135 degrees and 315 degrees from the top vertically (see FIGS. 4C1 and C2). It is located on the vertical plane (V3), and when it is more than 135 degrees and less than 315 degrees (see Fig. 4C3), it is ahead of the vertical plane (V3) passing through the central axis of the pin (9) It is made to be located. As a result, when the rotation angle of the arm (8) is 135 degrees and 315 degrees from vertically above, no rotational force acts on the third stirring paddle (5), but it also exceeds 135 degrees and less than 315 degrees. In some cases, the counterclockwise rotational force of FIG. 4 acts by its own weight. This rotational force is minimum when the rotation angle of the arm (8) is in the vicinity of 135 degrees from vertically above, gradually increases as the rotation angle increases, reaches a maximum at 225 degrees, and further exceeds 225 degrees. It gradually decreases and becomes a minimum near 315 degrees. The distance between the center axis of the pin (9) and the leading edge of the third stirring paddle (5) is determined by the distance between the center axis of the pin (9) and the inner peripheral surface of the peripheral wall (1a) of the heating tank (1). The leading edge of the third stirring paddle (5) is in contact with the inner peripheral surface of the peripheral wall (1a) of the heating tank (1) when the rotation angle of the arm (8) is 135 degrees and 315 degrees from above It is made to do. Therefore, the leading edge of the third stirring paddle (5) contacts the inner peripheral surface of the peripheral wall (1a) of the heating tank (1) when the rotation angle of the arm (8) is within the range of 135 to 315 degrees from vertically above. However, it does not contact within the range of more than 315 degrees and less than 135 degrees. In particular, when the rotation angle of the arm (8) exceeds 135 degrees and is less than 315 degrees from vertically above, the leading edge of the third stirring paddle (5) is heated to a heating tank with a predetermined force by the rotational force acting on it. It is pressed against the inner peripheral surface of the peripheral wall (1a) of (1). This pressing force is proportional to the rotational force. In addition, at the rear edge of the third stirring paddle (5), when the rotation angle of the arm (8) is more than 315 degrees and less than 135 degrees from vertically above, FIG. A stopper (5a) is provided for preventing excessive clockwise rotation.
[0019]
In the paddle stirring type powder heating apparatus having the above-described configuration, the powder (P) to be heated is put in the heating tank (1), and the peripheral wall (by the heat generated from the heating source while rotating the rotating shaft (2) ( Heat the powder (P) via 1a). The amount of the powder (P) put in the heating tank (1) is about half of the internal volume of the heating tank (1). As shown by the chain line in FIG. It exists in the range of 90 to 270 degrees. At this time, the front edge of the first agitation paddle (3) is located on the inner peripheral surface of the peripheral wall (1a) of the heating tank (1) when the rotation angle of the arm (6) is within the range of 90 to 270 degrees from vertically above. The leading edge of the second stirring paddle (4) is in contact with the inner peripheral surface of the peripheral wall (1a) of the heating tank (1) when the rotation angle of the arm (7) is within the range of 45 to 225 degrees from vertically above. The leading edge of the third stirring paddle (5) is in contact with the inner peripheral surface of the peripheral wall (1a) of the heating tank (1) when the angle of rotation of the arm (8) is within the range of 135 to 315 degrees from vertically above. Contact. Therefore, within a wide range of 45 to 315 degrees in the rotational direction with the vertical upper side being 0 degrees, the powder (P) and the like heated in the vicinity of the inner peripheral surface of the peripheral wall (1a) of the heating tank (1) and others The powder (P) in this portion is efficiently stirred and mixed, and the formation of a non-movable layer of the powder (P) along the inner peripheral surface of the peripheral wall (1a) is prevented. In particular, within the range of 90 to 270 degrees, where the vertical upper direction where the powder (P) is present is 0 degree, the leading edge of any stirring paddle is pressed against the inner peripheral surface of the peripheral wall (1a) with a relatively strong force. Therefore, within this range, the mixing is performed more efficiently, and the formation of a non-moving layer along the inner peripheral surface of the peripheral wall (1a) is surely prevented. Therefore, a decrease in the heating efficiency of the powder (P) in the tank (1) through the peripheral wall (1a) of the heating tank (1) due to heat generated from the heating source is prevented. As a result, it is not necessary to increase the amount of heat generated from the heating source, or to increase the heating tank (1) and lengthen the residence time of the powder (P) in the tank (1), thereby reducing costs. Can do. Further, since the formation of the non-moving layer is prevented, the sintering of the powder (P) in the non-moving layer can be prevented, and the generation of abnormal noise and the stirring paddle can be prevented from being worn or damaged.
[0020]
Next, an experimental example performed using the apparatus shown in FIG. 1 will be briefly described.
[0021]
The powder (P) containing Ca, Cl, S, and K as main components was placed in the heating tank (1) in approximately half of the internal volume of the heating tank (1). Then, while rotating the rotating shaft (2), the powder (P) was heated to 450 ° C. higher than the sintering temperature by the heat generated from the heating source. Such an operation was performed continuously for 10 days, and when the inside of the heating tank (1) was observed, a sintered layer of powder was not found.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an embodiment of a paddle stirring type powder heating apparatus according to the present invention.
FIG. 2 is a view corresponding to FIG. 1 and showing the operation of the first stirring paddle.
FIG. 3 is a view corresponding to FIG. 1 and showing the operation of the second stirring paddle.
FIG. 4 is a view corresponding to FIG. 1 and showing the operation of the third stirring paddle.
[Explanation of symbols]
(1): Heating tank
(1a): Perimeter wall
(2): Rotating shaft
(3) (4) (5): Stir paddle
(6) (7) (8): Arm

Claims (3)

A horizontal cylindrical heating tank closed at both ends, a rotating shaft rotatably disposed so as to be coaxial with the heating tank, a plurality of stirring paddles provided on the outer peripheral surface of the rotating shaft, and heating A paddle stirring type powder heating device provided with a heating source arranged around the peripheral wall of the tank,
A plurality of arms are provided radially and fixedly on the outer peripheral surface of the rotating shaft, and a stirring paddle is pivotally attached to the tip of each arm, and the tip of each stirring paddle is the inner peripheral surface of the peripheral wall of the heating tank Between the position in contact with the inner wall of the heating tank and the position separated from the inner peripheral surface of the peripheral wall of the heating tank. During one rotation, the tip of each stirring paddle is in contact with at least a part of the entire inner peripheral surface of the peripheral wall of the heating tank, and the rotation shaft is 1 at the same position in the length direction of the rotation shaft. A paddle agitation type powder heating apparatus provided with a plurality of agitation paddles in which the contact position of the tip part with the inner peripheral surface of the heating tank is shifted during rotation .   2. The paddle stirring type powder heating apparatus according to claim 1, wherein the stirring paddle swings by its own weight.   The contact position of the tip of the stirring paddle with the inner surface of the heating tank is determined by the pivoting position of the stirring paddle on the arm, the distance between the pivoting position and the tip of the stirring paddle, and the center of gravity of the stirring paddle. The paddle stirring type powder heating apparatus according to claim 1 or 2, which is configured as described above.

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