JP3249232B2 - Centrifugal thin film dryer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to the food industry, chemical industry,
The present invention relates to a centrifugal thin film dryer used in an industrial waste treatment industry, a water treatment industry, and the like.

[0002]

2. Description of the Related Art A centrifugal thin-film dryer is used for dehydration and dehydration of sludge with a high moisture content at a time to a low moisture content region where natural incineration is possible.
Since it can be dried, it has attracted attention in terms of energy saving and environmental protection.

[0003] Such a centrifugal thin film dryer includes a cylindrical heat transfer cylinder that is heated from the outside, and a main shaft rotatably disposed inside the heat transfer cylinder. A blade is attached to the main shaft, and the sludge introduced into the heat transfer drum is spread in a thin film form on the inner wall surface of the heat transfer drum by the blade. Then, the sludge dries as it descends along the inner wall of the heat transfer drum,
It is designed to be discharged from below. By the way, a central boss is attached to the lower part of the heat transfer drum, and the main shaft of the centrifugal thin film dryer is inserted and held in the central boss to restrict the movement in the radial direction.

As shown in the sectional view of FIG. 6 and the bottom view of FIG.
A cylindrical lower shaft flange 9 is attached, and a bearing 15 is fixed to the lower shaft flange 9 via a spoke 13. The bearing portion 15 has a bearing 14 and rotatably holds the lower shaft 2a of the main shaft 2. The lower shaft flange 9 is attached to the lower flange 16 of the heat transfer drum 1. Further, a discharge port 1b is formed below the spoke 13. A plurality of guide plates 8 are attached to a lower portion of the main shaft 2, and a gap g of about several mm is formed between the spokes 13 and the guide plates 8. The guide plate 8 functions as a guide when the main shaft 2 is inserted into the heat transfer drum 1 from above.

Further, a conventional structure for holding a main shaft by a boss portion will be described in more detail with reference to FIGS. 10 and 11. FIG. A bearing 15 is fixed to the lower shaft flange 9 via a spoke 13. The bearing portion 15 includes a center boss 32 fixed to the spoke 13 and a lower shaft guide 29 fixed to an inner surface of the center boss 32 so as to be detachable. The lower shaft guide 29 receives the lower shaft 20 attached to the lower end of the main shaft 2, and restricts the movement of the lower shaft 20 in the radial direction via the seal bearing 24.

That is, as shown in FIGS. 10 and 11, a collar 23 and a seal bearing 24 are sequentially inserted around the outer periphery of the lower shaft 20, and the collar 23 and the seal bearing 24 are provided.
The inner ring 24a is axially sandwiched and fixed between the step portion 33 of the lower shaft 20 and the bearing nut 25. The bearing nut 25 is screwed into the screw portion 21 of the lower shaft 20, and an auxiliary collar 26 is provided between the seal bearing 24 and the bearing nut 25 in order to secure a tool space when the bearing nut 25 is tightened. Is provided. The collar 23 is provided with a bearing housing 27 described later.
Extend in the radial direction so as to cover the upper part of the outer periphery.

On the outer periphery of the outer ring 24b of the seal bearing 24,
A cylindrical bearing housing 27 is fitted, and an outer ring 24b of the seal bearing 24 is axially moved inside the bearing housing 27 by a claw 27a provided at an upper portion of the bearing housing 27 and a housing nut 28 provided at a lower portion. Fixed. The outer periphery of the bearing housing 27 is
There are protruding portions 34 at different locations.

[0010] The projection 4 is provided on the outer periphery of the bearing housing 27.
The two projections 34 are adapted to abut on the inner peripheral surface of the lower shaft guide 29, thereby restricting the movement of the lower shaft 20 in the radial direction. One of the four convex portions 34 is housed in a concave portion 30 fixed to the lower shaft guide 29 side. The convex portion 34 and the concave portion 30 are circumferentially engaged with each other while being slidable in the axial direction. A cylindrical guide plate mounting base 22 that covers an upper portion of the lower shaft guide 29 is provided below the main shaft 2, and a plurality of guide plates 8 are fixed to the guide plate mounting base 22.

[0009]

When the sludge is dewatered and dried by such a centrifugal thin film dryer, when the water content of the dewatered sludge is 60% or less, the dewatered sludge becomes powdery and the guide plate 8 is formed. It falls, passes through the spokes 13, and is discharged from the discharge port 1b. However, the moisture content of the dewatered sludge is 60
%, The dewatered sludge 10 falls into a sticky mass and adheres to the guide plate 8 and the spokes 13 and the like.

The state of adhesion of such dewatered sludge will be described with reference to a sectional view of FIG. 8 and a bottom view of FIG. As shown in FIGS. 8 and 9, the dewatered sludge 10 that has fallen below the heat transfer drum 1 initially adheres to the spokes 13 and the corner inside the lower shaft flange 9. Next, the dewatered sludge 10 forms a bridge between the upper surface of the spoke 13 and the lower shaft flange 9 as in the dewatered sludge 10a shown in FIG. Then, when the bridge is formed, the amount of adhering dewatered sludge increases over time, as in the case of dewatered sludge 10b shown in FIG.
As the time elapses further, the dewatered sludge fills the gaps between the spokes 13 and becomes layered as in the dewatered sludge 10c shown in FIG. As described above, the dewatered sludge 10 clogging between the spokes 13 also adheres to the guide plate 8 and fills the space between the guide plates 8. In this case, a lump of the dewatered sludge 10 is sandwiched between the inner surface of the heat transfer drum 1 and the outer end of the guide plate 8, causing an overload and causing the motor 7 to trip. In order to maintain the normal operation state of the centrifugal thin-film dryer, it is necessary to prevent such blockage by the dewatered sludge 10.

By the way, it has been confirmed from past experiments that the amount of liquid supplied to the centrifugal thin film dryer can be kept substantially constant even when the water content at the inlet changes. Therefore, for example, in consideration of drying the sewage sludge, when the sludge having a water content of about 99 to 95% at the inlet of the centrifugal thin film dryer is dried to a water content of about 50%, the solid content in the centrifugal thin film dryer is Since the amount is small and the amount of water including the sludge at the lower part of the centrifugal thin film dryer is relatively large, there is little possibility that the solid content of the sludge will be scattered as fine powder. However, the water content at the inlet of the centrifugal thin film dryer is relatively low at less than 95%,
When the water content at the outlet is also about 30 to 40%, the amount of solids remaining in the centrifugal thin film dryer increases, and the state of sludge at the bottom of the centrifugal thin film dryer also contains less moisture and is scattered. In many cases, it is relatively easy to obtain a fine powder.

In the conventional centrifugal thin film dryer, the seal bearing 24 is opened to the outside (processing area) through the gap between the guide plate mounting base 22 and the lower shaft guide 29 and the gap between the collar 23 and the bearing housing 27. Has become. Therefore, when the centrifugal thin film dryer is operated under conditions that generate a large amount of fine powder that is easily scattered as in the latter example, the fine powder gradually accumulates on the seal bearing 24 through the narrow gap. I do. Although the seal bearing 24 has a certain degree of dust resistance, if the fine powder is continuously rotated for a long time in a state where the fine powder is accumulated, the fine powder gradually becomes a seal bearing 24.
It may penetrate inside and cause damage.

The present invention has been made in view of the above-mentioned circumstances, and has an object to prevent dewatered sludge from being clogged in a gap between a bearing flange and a spoke and generate a large amount of scattered fine powder. It is an object of the present invention to provide a highly reliable centrifugal thin film dryer in which bearings are not damaged even under operating conditions.

[0014]

In order to achieve the above object, a first aspect of the present invention is a cylindrical heat transfer apparatus which is heated by a heating device and has a sludge inlet at an upper portion and a sludge outlet at a lower end. A main shaft having a body, a blade, and rotatably disposed in the heat transfer cylinder; a bearing portion for supporting a lower end of the main shaft so as not to swing during rotation; and the bearing portion and the heat transfer device. A ring-shaped bearing flange attached to the lower end of the heat transfer drum to fix the lower end of the drum, and a centrifugal thin-film dryer having a plurality of spokes joining the bearing flange and the bearing portion, the outer surface of the bearing flange. It is characterized by comprising a hole-shaped blast nozzle communicating with the inner surface, and a compressed gas source for supplying a compressed gas to the blast nozzle.

[0015]

[0016]

In the centrifugal thin film dryer according to the first aspect of the present invention, when the compressed gas source for supplying the compressed gas is activated, the gas is gushered from the blast nozzle on the inner surface of the bearing flange to the inside of the bearing flange. At this time, the dewatered sludge adhering to the inner surface of the bearing flange is removed, so that the gap between the bearing flange and the spoke is not blocked by the dewatered sludge.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an overall sectional view of a centrifugal thin film dryer according to one embodiment of the present invention. In FIG. 1, the centrifugal thin film dryer includes a thin heat transfer cylinder 1, and a main shaft 2 is provided inside the heat transfer cylinder 1 coaxially with the heat transfer cylinder 1. It has become. The main shaft 2 has a motor 7
Is held in the axial direction.
A distribution ring 3 is provided for dispersing the sludge 6 supplied from the sludge inlet 1 a into the heat transfer drum 1 along the inner surface of the heat transfer drum 1. Further, a blade 4 for thinning the sludge 6 dispersed on the inner surface of the heat transfer drum 1 is attached over the entire length of the main shaft 2.

Since the blade 4 moves while keeping a very small gap between the blade 4 and the heat transfer cylinder 1, a large solid content may be entrapped. In order to prevent the abnormality due to the biting or the like, the root of the blade 4 has a hinge shape so that the blade 4 can escape. A steam jacket 5 serving as a heat source for dewatering and drying sludge is provided outside the heat transfer drum 1, and heated steam flows into the steam jacket 5 from a steam inlet 5a and flows out from a steam outlet 5b. It has become.

As shown in the lower sectional view of FIG. 2 and the bottom view of FIG.
A cylindrical lower shaft flange 9 is attached to the lower flange 16. Further, a bearing portion 15 is fixed to the lower shaft flange 9 via a spoke 13. This bearing portion 15 has the same structure as the conventional one shown in FIG.
Is rotatably held.

A plurality of guide plates 8 are attached to a lower portion of the main shaft 2, and a gap g of about several mm is formed between the guide plates 8 and the spokes 13. Further, a discharge port 1b is formed below the spoke 13.

Here, a plurality of blast nozzles 18 are formed in the bearing flange 9 and extend from the outer surface to the inner surface. The opening on the inner surface side of the lower shaft flange 9 of the blast nozzle 18 is provided toward a corner portion 11 formed by the inner surface side of the lower bearing flange 9 and the spokes 13. Further, a connection pipe 17 is attached to an opening on the outer surface side of the lower shaft flange 9 of the blast nozzle 18, and a compressor 19 is connected to the opposite side of the connection pipe 17.

Next, the operation of this embodiment will be described.
The sludge 6 supplied into the heat transfer cylinder 1 from the sludge inlet 1a is
Heat transfer cylinder 1 by distribution ring 3 rotating with main shaft 2
Dispersed along the inner surface. Furthermore, the sludge 6 can be supplied to the main shaft 2
The heat transfer drum 1 is stretched in a thin film form on the inner surface of the heat transfer drum 1 by the blade 4 rotating with the blade. Then, the sludge 6 in the form of a thin film gradually falls downward due to gravity and the pressure of new sludge supplied one after another. At this time, the heating steam supplied to the steam jacket 5 outside the heat transfer drum 1 causes
The sludge 6 is heated by the heat transfer cylinder 1. Thereafter, the sludge 6 is dehydrated by evaporating its water content, and becomes a dewatered sludge 10 to be discharged from a discharge port 1b provided at the lower end of the heat transfer drum 1.
On the other hand, the moisture evaporated from the sludge 6 is exhausted outward from an exhaust port 12 provided at the upper part of the heat transfer drum 1.

Next, the process of passing the dewatered sludge 10 from the lower part of the heat transfer cylinder 1 through the discharge port 1b will be described in detail. The dewatered sludge 10 dewatered by the heat transfer cylinder 1 becomes a lump,
After passing through a plurality of rotating guide plates 8, a plurality of spokes 1
Fall through the gap between the three. However, a part of the dewatered sludge 10 accumulates on the upper surface of the spoke 13. The dewatered sludge 10 thus deposited is pushed laterally by the guide plate 8 and falls through the gap between the spokes 13. Therefore, only the dewatered sludge remaining in the gap g between the guide plate 8 and the spoke 13 remains. However, the amount of the dewatered sludge 10 remaining in the gap g is small and hardly affects the operation.

On the other hand, another part of the dewatered sludge 10 adheres to a corner portion 11 formed by the inner surface of the lower shaft flange 9 and the spokes 13. Here, when the compressor 19 is started, the compressed air is supplied to the blast nozzle 18 through the connection pipe 17, and further, from the opening on the inner surface side of the lower shaft flange 9 of the blast nozzle 18 toward the corner 11. The air is blown vigorously, and the dewatered sludge 10 attached to the corner 11 is removed. Therefore, the spoke 13
A bridge of the dewatered sludge is not formed between the lower shaft flange 9 and the lower shaft flange 9, and the gap between the spokes 13 is not filled with the dewatered sludge.

According to the present embodiment, the dewatered sludge 10 which is dewatered and dropped by the heat transfer drum 1 does not adhere to the inner surface of the lower shaft flange 9 or the outer surface of the bearing portion 15 without being attached to the lower shaft flange 9 and the bearing. The liquid passes through the space 15 smoothly and is discharged from the discharge port 1b. Therefore, clogging by the dewatered sludge 10 can be more reliably prevented.

FIG. 4 is a sectional view of a centrifugal thin film dryer according to another embodiment of the present invention. In FIG. 4, the centrifugal thin-film dryer includes a thin-walled heat transfer cylinder 1, a main shaft 2 provided inside the heat transfer cylinder 1 coaxially with the heat transfer cylinder 1, and a motor 7 for driving the main shaft 2 to rotate. I have. The axial load of the main shaft 2 is supported by the motor 7. A sludge inlet 1a is provided at an upper portion of the heat transfer drum 1, and a sludge inlet 1a is provided at an upper portion of the main shaft 2.
A distribution ring 3 for dispersing the sludge 6 supplied into the heat transfer cylinder 1 from along the inner surface of the heat transfer cylinder 1 is fixed.
Further, the main shaft 2 is provided with a blade 4 for thinning the sludge dispersed on the inner surface of the heat transfer drum 1 by the distribution ring 3 over the entire length. Since the blade 4 moves while maintaining a very small gap between the blade 4 and the heat transfer cylinder 1, the solid content of the large sludge 6 may be trapped. In order to prevent the abnormality due to the biting or the like, the root of the blade 4 on the side of the main shaft 2 has a hinge shape so that the blade 4 can escape.

On the other hand, on the outside of the heat transfer cylinder 1, dewatering of sludge
A steam jacket 5 serving as a heat source for drying is provided, and hot steam flows into the steam jacket 5. The steam flows into the steam jacket 5 from the steam inlet 5a, and the steam in the steam jacket 5 flows out from the steam outlet 5b. Further, an exhaust port 12 for exhausting the evaporated vapor generated from the sludge is provided at an upper portion of the heat transfer drum 1.

Next, a structure for holding the main shaft 2 by the lower portion of the heat transfer drum 1 will be described with reference to FIG. However, since the basic holding structure is the same as that of the conventional example, only the differences from the conventional example will be described here.

As shown in FIG. 5, in this embodiment, the color 3
9 is changed to a U-shape having a space inside, and a collar 35 is newly provided between the claw 27a on the upper part of the cylindrical bearing housing 27 and the seal bearing 24. An L-shaped rubber sealing material 37 is fitted inside the collar 39, and the lip 37 a of the sealing material 37 is in contact with the collar 35 so as to be pressed against the collar 35.

Further, the auxiliary collar 36 provided below the seal bearing 24 is formed into an L-shape,
0 is also changed to an L-shape, and the lip portion 38 a of the L-shaped rubber sealing material 38 fitted in the auxiliary collar 36 is in contact with the housing nut 40 so as to be pressed against the housing nut 40. Color 3
The contact surface between the housing 5 and the lip portions 37a, 38a of the sealing members 37, 38 of the housing nut 40 is subjected to hard chrome plating.

Next, the operation of the present embodiment will be described.
In FIG. 4, the sludge 6 supplied into the heat transfer cylinder 1 from the sludge inlet 1a is dispersed along the inner peripheral surface of the heat transfer cylinder 1 by the distribution ring 3 rotating together with the main shaft 2. Further, the sludge 6 is rotated by the blade 4 rotating with the main shaft 2.
The heat transfer drum 1 is stretched into a thin film on the inner surface.

The sludge 6 in the form of a thin film gradually moves downward due to gravity and the pressure of new sludge supplied one after another. At that time, the sludge 6 is heated by the heat transfer cylinder 1 by the heating steam supplied to the steam jacket 5 outside the heat transfer cylinder 1. Thereafter, the sludge 6 is dehydrated by evaporating the water to become dehydrated sludge 10, and is discharged from a discharge port 1 b provided at a lower end of the heat transfer drum 1.

When the centrifugal thin-film dryer is operated, the periphery of the lower portion of the main shaft 2 becomes an atmosphere containing many scattered fine powders depending on the operating conditions. In this case, some fine powder may enter the inside of the guide plate mounting base 22 through the gap between the guide plate mounting base 22 and the lower shaft guide 29 shown in FIG. Even if dust that has entered the inside of the guide plate mounting base 22 enters between the collar 39 and the bearing housing 27,
The sealing material 37 prevents fine powder from accumulating in the seal bearing 24. Since the lower portion of the seal bearing 24 is similarly sealed by the seal member 38, the fine powder does not adversely affect the seal bearing 24.

Further, the collar 35 and the housing nut 4
The hard chrome plating treatment applied to the contact surfaces of the sealing materials 37, 38 with the lip portions 37a, 38a improves the surface roughness of the contact surfaces. This has the effect of suppressing wear of parts due to rotational friction with 37a and 38a.

[0035]

As described above, according to the first aspect of the present invention,
According to the centrifugal thin film dryer, no dewatered sludge adheres to the side surfaces of the spokes, so the gaps between the spokes are not blocked by the dewatered sludge, and the rotation of the main shaft can be performed smoothly and normal Operation can be continued.

[Brief description of the drawings]

FIG. 1 is an overall sectional view of a centrifugal thin film dryer according to one embodiment of the present invention.

FIG. 2 is a lower sectional view of FIG. 1;

FIG. 3 is a bottom view as seen from the II direction of FIG. 2;

FIG. 4 is an overall sectional view of a centrifugal thin film dryer according to another embodiment of the present invention.

FIG. 5 is a lower sectional view of FIG. 4;

FIG. 6 is a lower sectional view of a conventional centrifugal thin film dryer.

FIG. 7 is a bottom view as seen from the II-II direction in FIG. 6;

FIG. 8 is a cross-sectional view showing the state of attachment of dewatered sludge in a conventional centrifugal thin film dryer.

FIG. 9 is a bottom view as seen from the III-III direction of FIG. 8;

FIG. 10 is a sectional view of a lower bearing portion of a conventional centrifugal thin film dryer.

FIG. 11 is a bottom view as seen from the VI-VI direction in FIG. 10;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Heat transfer drum, 2 ... Main shaft, 2a ... Lower shaft, 3 ... Distribution ring, 4 ... Blade, 5 ... Steam jacket, 6 ... Sludge, 7
... Motor, 8 ... Guide plate, 9 ... Lower shaft flange, 10,
10a, 10b, 10c: dewatered sludge, 11: corner,
12 ... exhaust port, 13 ... spoke, 14 ... bearing, 1
5 bearing part, 16 lower flange, 17 connection pipe,
18 ... Fume Nozzle, 19 ... Compressor, 20 ... Lower Shaft, 21 ... Screw, 22 ... Guide Plate Mounting Base, 23 ... Collar, 24 ... Seal Bearing, 24a ... Inner Ring, 24b ... Outer Ring, 25 ... Bearing Nut, 26 ... Auxiliary color, 27
... bearing housing, 27a ... claw, 28 ... housing nut, 29 ... lower shaft guide, 30 ... recess, 31 ... dust clearance, 32 ... central boss, 33 ... step, 34 ... convex, 35, 39 ... Color, 36 ... Auxiliary color, 37, 3
8: sealing material, 37a, 38a: lip portion, 39: collar, 40: housing nut.

Claims (1)

(57) [Claims] 1. A cylindrical heat transfer cylinder which is heated by a heating device and has a sludge inlet at an upper portion and a sludge outlet at a lower end, a blade, and is rotatably disposed in the heat transfer drum. A main shaft, a bearing for supporting the lower end of the main shaft so as not to swing during rotation, and a ring-shaped bearing flange attached to the lower end of the heat transfer drum to fix the bearing and the lower end of the heat transfer drum. In a centrifugal thin-film dryer including the bearing flange and a plurality of spokes that join the bearing portion, a hole-shaped blast nozzle communicating from the outer surface to the inner surface of the bearing flange, and a compressor for supplying a compressed gas to the blast nozzle. A centrifugal thin-film dryer comprising a gas source.