JP2008136972A - Vertical-type roller mill - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vertical-type roller mill having high stiffness, capable of suppressing the generation of oscillations and also suppressing manufacturing costs. <P>SOLUTION: The vertical-type roller mill 1 has the structure that a plurality of rollers 10 each supported by a base 31 with a rockable arm 11 are pressed on a rotary table 2 inside a mill casing 5. The base 31 is made from concrete being integral with base concrete 30 installing the rotary table 2 and its drive means. It is sprcifically preferable that, while fixing a metallic bedplate 20 above the base 31, a bearing case 13 for supporting a rocking shaft 12 of the arm 11 is mounted on the upper surface of the bedplate 20 with a replaceably arranged thin liner 13a in a height-adjustable manner. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The invention according to the claims relates to a vertical roller mill which is a facility for pulverizing coal, cement raw material, and the like using a rotary table and a roller.

  The structure of a conventional general vertical roller mill is shown in FIG. A rotary table 2 is installed so as to be able to rotate around a vertical axis, and a motor 3 and a speed reducer 4 as drive sources are connected to the rotary table 2, and a plurality of (generally 2 to 4 around the rotary table 2 are provided. ) Rollers 10 are arranged, and each roller 10 is configured to be pressed against the upper surface of the table 2. The rotary table 2 and the roller 10 are covered with a cylindrical mill casing 5, and the casing 5 is provided with a raw material inlet 6, a hot air inlet 7, a pulverized fine powder outlet 8, and the like. Yes. In addition, the structure of such a vertical roller mill is described in Patent Document 1 and the like described later.

  The raw material supplied from the inlet 6 is placed on the turntable 2, moved to the vicinity of the outer periphery by the action of centrifugal force accompanying the rotation, and is crushed by being reduced by the roller 10. The pulverized raw material is blown up to the upper part of the casing 5 while being dried by hot air sent from the introduction port 7. The fine powder pulverized to a sufficiently fine level is sent out from the take-out port 8 near the upper end, and the other fine powder is supplied again to the rotary table 2 through the separator 9 in the casing 5 and pulverized again. Thus, the fine powder pulverized to a substantially constant particle size is recovered.

  A roller 10 pressed onto the rotary table 2 is attached to an upper end portion of an arm 11 that swings about a shaft (swing shaft) 12, and a lower portion of the arm 11 is connected to a distal end portion of a hydraulic cylinder 15. Has been. When the hydraulic cylinder 15 whose base end portion is connected to the foundation concrete 30 is contracted, the arm 11 swings, and the roller 10 is pressed onto the rotary table 2.

The arm 11 to which the roller 10 is attached is supported by a gantry at the portion of the swing shaft 12, and the gantry is conventionally a stand 31 'separate from the foundation concrete 30 by a steel plate (or cast steel). Is formed. A bearing box (bearing case) that supports the swing shaft 12 of the arm 11 is integrally provided on the stand 31 ′ made of a steel plate or the like.
Japanese Utility Model Publication No. 3-52107

  When the above-mentioned arm including the roller is supported by a stand made of a steel plate or the like, the stand needs to be configured with high rigidity by using a large amount of a thick steel plate, which is a considerable weight. This is because the pressing force of the roller against the rotary table is large (the pressing force of one roller may be several hundred tons), so the force required to support the arm is also large, and the vibration that occurs as the raw material is crushed is suppressed. The reason is that it is necessary. When the vertical roller mill becomes large, the weight of the stand increases at a ratio of the square to the third power of the dimensional ratio, and the production cost of the stand generally increases in a similar manner.

  In view of such problems, the invention according to the claims provides a vertical roller mill that has high rigidity and can suppress the generation of vibrations and can also reduce the manufacturing cost.

In the vertical roller mill according to the present invention, a plurality of rollers each supported by a gantry via a swingable arm (that is, the angle can be changed about a swing axis) rotate inside the mill casing. With respect to a structure that is pressed onto a table, the gantry is formed of concrete that is integral with the foundation concrete on which the rotary table is installed.
Since the unit weight of concrete is about 2-3% of that of steel plate, if the pedestal is made of concrete integrated with the basic concrete, the cost can be greatly reduced compared to the case of using a stand made of steel plate. Is possible. In addition, for example, concrete that is appropriately constructed without providing a hollow portion or the like has high rigidity, so that vibration caused by pulverization can be effectively damped. Since the frame can be formed by placing it at the same time as the foundation concrete, there is also an advantage that the construction period can be shortened.

The vertical roller mill of the invention further includes a thin plate liner in which a metal base plate is fixed to the upper portion of the gantry and a bearing case supporting the swing shaft of the arm is replaceably disposed on the upper surface of the base plate. It is preferable that the height can be adjusted via.
When the gantry is made of concrete, there is a problem due to concrete-specific sedimentation (shrinkage), unlike the case of steel plates. When the height of the gantry is 4 m, for example, the height of the upper surface (the portion to which the arm bearing is attached) is often lowered by a total of about 10 mm due to settling for several months.
As described above, when the bearing case is attached to the upper surface of the metal base plate provided on the upper portion of the gantry via the replaceable height adjusting thin plate liner, the influence due to the sedimentation of the concrete can be avoided. This is because a replaceable thin liner is used so that the height of the bearing case can be easily adjusted during periodic inspections. If the height of the bearing case changed by sedimentation of the concrete is not corrected, the height of the roller relative to the rotary table will be inappropriate, and the thickness (layer thickness) of the material to be crushed between the two will change. The vibration accompanying crushing becomes intense.

Further, it is particularly preferable that the metal base plate is attached to the upper portion of the gantry using an installation liner together with an embedded bolt (foundation bolt) to the gantry and the periphery is hardened with mortar.
In this way, if a metal base plate is attached to the top of a concrete base using an installation liner, regardless of the height of the base made of concrete, etc. (the dimensional accuracy is lower than that of a base made of steel, etc.) It is possible to increase the installation accuracy of the metal base plate. The metal base plate is attached to the base with embedded bolts, and the periphery is hardened with mortar, so it can be firmly fixed in place.
When the metal base plate is thus mounted on the gantry, an installation liner is used between the base plate and the gantry, and a thin plate liner is used between the base plate and the bearing case. Once the metal base plate is fixed, it is difficult to replace the installation liner. Therefore, the settling of the concrete is dealt with by replacing the thin plate liner.

When a fluid pressure cylinder connected to a fixed member on foundation concrete is connected to the arm in order to press each roller on the rotary table, each connection portion in the cylinder (that is, the connection portion with the arm and the foundation concrete). The inclination of the connecting pin (used for the connecting portion of the cylinder) or the shaft (the swinging shaft) is allowed in the bearing supporting the swinging shaft of the arm and the bearing supporting the swinging shaft of the arm. It is advantageous to use each of them (including a self-aligning type bearing or bush) including spherical members (that is, aligning).
Depending on the concrete settling condition, the swing axis on the gantry may be tilted from the initial position. The tilt can be corrected by appropriately replacing the thin plate liner at the next periodic inspection, etc., but at least during the period until the inspection, etc., the swinging shaft tilts and the arm tilts. The connecting pin of each connecting part of the fluid pressure cylinder operates in an inclined state. In this regard, if a spherical member is used for each connecting portion of the cylinder and the bearing of the swing shaft of the arm as described above, the connecting portion and the bearing are also in the period until the inclination is corrected by the thin plate liner. Unreasonable force does not act and abnormal damage or the like can be avoided.

The above pedestals that support each roller are provided at regular intervals (including the case of substantially equal intervals) around the rotary table, and the adjacent casings are connected by connecting beams, and the mill casing is placed on the connecting beams. It is further preferable that the low-friction member is attached so as to be slidable (relatively displaced while being in contact) in the inner / outer direction (inner / outer direction / radial direction of the mill casing).
A configuration in which adjacent frames are connected by a connecting beam and a mill casing is mounted thereon is also employed when the frame is configured by a stand made of steel plate or the like. In that case, the mill casing was fixed on the connecting beam by welding or the like. The mill casing rises in temperature and expands due to the action of the hot air blown in, but the thermal expansion is absorbed by elastic deformation of the steel plate or the like constituting the stand, so even in such a conventional configuration, the mill casing There was no particular problem.
However, since a frame made of concrete cannot be expected to be elastically deformed in the same manner as a steel plate or the like, a means for preventing an increase in stress due to thermal deformation of the mill casing is required. In consideration of this point, the above is a method in which a mill casing is slidably mounted on a connecting beam with a low friction member interposed therebetween. By doing so, even when the mill casing expands and contracts due to temperature changes, the relative friction between the connecting beam and the connecting beam occurs due to the action of the low friction member, and the mill casing stress is smoothly eliminated and reduced. This prevents the occurrence of defects.
When the gantry is formed of concrete that is integral with the foundation concrete, the gantry is provided with sufficient strength. Therefore, the connecting beam does not need to have a role of reinforcing the gantry. Therefore, the connecting beam only needs to support the weight of the mill casing, which has the advantage of simplifying the connecting beam and reducing its manufacturing cost.
In order to connect the adjacent frames, for example, the metal base plates fixed on the frame may be connected by a connecting beam. This is because various connecting means can be used more easily between the metal base plates than between the concrete bases.

  According to the vertical roller mill of the invention according to the claims, it is possible to greatly reduce the cost as compared with the conventional one, and to effectively suppress the vibration accompanying the pulverization. There is also an advantage that the construction period can be shortened.

If a thin plate liner is used at the mounting portion of the bearing case that supports the swing shaft of the arm, the problem caused by concrete settling can be solved.
If a bearing including a spherical member is used for the connecting portion of the fluid pressure cylinder that presses the roller and the bearing that supports the swing shaft of the arm, the inconvenience due to the settling of concrete can be more effectively eliminated.
If the mill casing is mounted on the connecting beam between the stands with the low friction member interposed therebetween, it is preferable that the thermal stress of the mill casing is smoothly eliminated or reduced.

  One form regarding implementation of invention is shown in FIGS. FIG. 1 is an overall view of a vertical roller mill 1 and a part thereof is shown in cross section. 2 is a detailed view of the gantry 31 and the like that support the roller 10 in FIG. 1, and FIG. 2 (a) is a cross-sectional view seen from the side (a-a cross-sectional view in FIG. 2 (b)), FIG. 2B is a rear view. 3 is a plan view of the rotary table 2 and the like in FIG. 1 as viewed from above, and FIG. 4 is a detailed view of a portion IV in FIG.

  A vertical roller mill 1 shown in FIG. 1 is a facility for pulverizing raw materials such as coal, cement raw material, and blast furnace slag by a rotary table 2 and three rollers 10 pressed against the raw material. The overall height of the exemplified equipment is about 20 meters, and the pressing force of one roller 10 against the rotary table 2 is a relatively large size of about 270 tons.

  The outline of the structure and function of the vertical roller mill 1 is the same as that of the conventional roller mill described with reference to FIG. That is, first, the rotary table 2 is installed on the foundation concrete 30 so as to be able to rotate about the vertical axis, and the motor 3 and the speed reducer 4 which are driving sources thereof are connected to the rotation table 2, and again on the foundation concrete 30. Is provided. As the roller 10, a roller body rotatable around a shaft 10 a is attached to an upper portion of a swingable arm 11, and the arm 11 is supported on a swinging shaft 12 so as to be swingable and displaceable. The lower part is connected to the tip of the hydraulic cylinder 15. Since the hydraulic cylinder 15 has a base end connected to the fixing member 16 on the foundation concrete 30, when the force is generated in the contracting direction, the arm 11 is swung to press the roller 10 onto the rotary table 2. (In other words, the raw material can be sandwiched between the roller 10 and the table 2). In the vicinity of the outer periphery of the table 2, a concave surface portion 2a that is easy to hold the raw material is formed in a groove shape, and the peripheral surface of the main body of the roller 10 is pressed against the concave surface portion 2a. However, since the concave surface portion 2a of the table 2 and the main body of the roller 10 are formed of a hard material having high crushing performance, they are prevented from coming into direct contact with each other to prevent cracking. The planar positional relationship between the rotary table 2 and the roller 10 or the like pressed against the concave surface portion 2a is as shown in FIG.

  The rotary table 2 and each roller 10 are covered with a cylindrical mill casing 5, and the casing 5 has a raw material inlet 6, a hot air inlet 7, and a pulverized fine powder outlet 8. Etc. are provided. The raw material supplied from the inlet 6 is placed on the turntable 2, moved to the concave portion 2 a near the outer periphery by the action of centrifugal force accompanying the rotation, and is crushed by being pressed down by the roller 10. As described above, the pulverized raw material is blown up to the upper part while being dried by the hot air sent from the inlet 7, and the fine powder pulverized to a sufficiently fine level is recovered from the upper outlet 8. The non-fine one is again supplied onto the rotary table 2 through the separator 9 in the casing 5 and pulverized again. By repeating these steps, the fine powder pulverized to a substantially constant particle size is recovered from the outlet 8.

  In this vertical roller mill 1, the gantry 31 that supports the arm 11 to which the roller 10 is attached is supported by the rocking shaft 12, and is formed of concrete that is integral with the foundation concrete 30. In addition to the reinforcing bars that are continuous from the inside of the foundation concrete 30, the concrete 31 is placed at the same time as the foundation concrete 30 is placed.

If the pedestal 31 is made of concrete, the equipment cost can be reduced compared to the case where the pedestal is made of a steel plate stand, and the pedestal 31 has sufficient rigidity and strength to effectively vibrate during raw material crushing. Can be suppressed. However, on the other hand, the following new technical problems arise. That is, a) dimensional accuracy such as height is not as high as that of a steel plate or the like, and b) a steel part such as a member for supporting the swing shaft 12 of the arm 11 cannot be welded to concrete. It is necessary to devise the mounting mode. C) Since the concrete shrinks after it has hardened, the height and other changes occur due to settling over several months, and the crushing condition of the raw material by the table 2 and the roller 10 is inappropriate. D) Since the amount of concrete that can be elastically deformed is extremely small, there are considerations for eliminating thermal stress at the connection part between the part that undergoes deformation due to thermal expansion and the mount 31. It is a problem that it is necessary.
In consideration of such technical problems, the vertical roller mill 1 employs the following configuration in relation to the gantry 31.

  First, as shown in FIG. 2 (a), the upper part of the concrete base 31 is made of a metal (steel) using a foundation liner 22 embedded in the base 31 and a sloped installation liner 21 whose thickness can be easily set. (Made) base plate 20 is fixed. When fixing, a recess 31a is formed in advance on the top of the pedestal 31, and the base plate 20 is fixed to the recess 31a as described above, and the concave plate 31 is filled with mortar to fix the position of the base plate 20. . If the metal base plate 20 is fixed in this way, members (such as a bearing case 13 and a connecting beam 33 described later) that support the swing shaft 12 of the arm 11 can be easily attached to the base plate 20. Although it is difficult to increase the accuracy of the height of the concrete base 31 and the level of the upper surface thereof, the accuracy of the height and level of the base plate 20 is sufficiently high by using the installation liner 21 as described above. can do.

On the upper surface of the base plate 20 fixed as described above, a bearing case (bearing box) 13 that supports the swing shaft 12 of the arm 11 is attached with a replaceable thin plate liner 13a and attached with bolts 13c. . A thin plate liner 13b for adjusting the front-rear position is inserted between the shoulder portions of the base plate 20. Even if the height of the base plate 20 changes due to the sedimentation of the concrete, the height of the bearing case 13 and the height of the roller 10 do not change if the thin plate liner 13a is replaced with a different thickness. No fluctuation occurs in the pulverization of the raw material on 2. By replacing the thin plate liner 13b, the front and rear positions of the bearing case 13 and the like can be readjusted.
Reference numeral 32 in FIG. 2A is a stopper for the arm 11 and is attached to the front portion of the gantry 31 so that the amount of protrusion can be adjusted. If the amount of protrusion of the stopper 32 is set appropriately, it is possible to avoid the arm 11 from being excessively displaced and the roller 10 to directly contact the rotary table 2.

  As shown in FIG. 2 (b), the bearing case 13 is provided at two positions on the left and right sides of the gantry 31 and supports the swing shaft 12 of the arm 11 horizontally. The height of the case 13 may not be the same, and the shaft 12 may not be horizontal. Even in such a case, the arm 11 is swung smoothly so that the force of the fluid pressure cylinder 15 is transmitted to the roller 10 correctly and smoothly. The connecting portion employs a structure including a spherical member that can permit the inclination of the shaft 12 and the connecting pins 15a and 15b. In other words, a self-aligning type bearing 14 is used as the bearing 14 in the bearing case 13, and an aligning bearing or bush is also assembled to the connecting pins 15 a and 15 b used at the connecting portions at both ends of the cylinder 15. .

The mill casing 5 shown in FIG. 1 is attached to and supported by a connecting beam 33 provided between the gantry 31. The connecting beam 33 is made of steel, and is connected to the side surface of the metal base plate 20 fixed on the base 31 so as to connect the adjacent bases 31.
While the mill casing 5 rises in temperature due to hot air sent from the introduction port 7 and undergoes thermal expansion, the basic concrete 30 and the mount 31 have little temperature change and hardly expand, and the amount that can be elastically deformed is extremely high. It is slight. The connecting beams 33 that connect between the gantry 31 also have little change in temperature and are short, so that they hardly expand and the amount of elastic deformation is also small.
Therefore, as shown in FIG. 4, the connection between the connecting beam 33 and the mill casing 5 is performed with a low friction member 34 interposed therebetween. Specifically, a liner made of Teflon (registered trademark) is sandwiched between the upper surface of the connecting beam 33 and the lower surface of the flange member 5a of the mill casing 5, and the space between the connecting beam 33 and the flange member 5a is between the casing 5 and the flange member 5a. The bolts and nuts 5b are joined so that they can slide relatively inward and outward (left and right in FIG. 4). In this way, even if the mill casing 5 undergoes thermal expansion (and contraction), generation of inappropriate stress and the like can be avoided.
Instead of the structure shown in FIG. 4, it is also conceivable to provide a support member that can absorb thermal expansion displacement, such as a steel plate or a pipe, on the foundation concrete 30, thereby supporting the mill casing 5 directly. However, in that case, the structure tends to be complicated due to the relationship between the arm 11 and the duct of the hot air inlet 7.

1 is an overall view showing a vertical roller mill 1 as an embodiment of the invention, and a part thereof is shown by a cross section. 2A and 2B are detailed views of the gantry 31 and the like that support the roller 10 in FIG. 1. FIG. 2A is a cross-sectional view seen from the side (a-a cross-sectional view in FIG. 2B), and FIG. It is a rear view. It is the top view which looked at the rotary table 2 grade | etc., In FIG. 1 from upper direction. It is detail drawing which shows the connection part of IV section in FIG. 1, ie, the connection beam 33, and the mill casing 5. FIG. It is a general view which shows the conventional common vertical roller mill, and has shown one part by the cross section.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vertical roller mill 2 Rotary table 5 Mill casing 10 Roller 11 Arm 12 Oscillating shaft 13 Bearing case 13a Thin plate liner 15 Fluid pressure cylinder (hydraulic cylinder etc.)
20 Metal base plate 21 Installation liner 30 Foundation concrete 31 Base 33 Connecting beam

Claims (5)

A plurality of rollers each supported by a gantry via a swingable arm is a vertical roller mill having a structure that is pressed against a rotary table inside a mill casing,
A vertical roller mill characterized in that the gantry is made of concrete integrated with basic concrete on which the rotary table is installed.   A metal base plate is fixed to the top of the pedestal, and the height of the bearing case that supports the pivot shaft of the arm can be adjusted via a thin plate liner that can be replaced on the top surface of the base plate. The vertical roller mill according to claim 1, wherein the vertical roller mill is attached as described above.   3. The metal base plate according to claim 2, wherein the metal base plate is attached to an upper portion of the base using an installation liner together with an embedded bolt or an embedded metal to the base, and the periphery thereof is hardened with mortar. Vertical roller mill.   In order to press each roller on the rotary table, a fluid pressure cylinder connected to a fixed member on the foundation concrete is connected to the arm, and supports each connecting portion in the cylinder and the swing shaft of the arm. The saddle type roller mill according to claim 2 or 3, wherein the bearing includes a spherical member that allows inclination with respect to the connecting pin or the shaft. The cradle for supporting each roller is provided at equal intervals around the rotary table, and the adjacent cradles are connected by a connecting beam,
The vertical roller mill according to any one of claims 1 to 4, wherein the mill casing is mounted on the connecting beam so as to be slidable inward and outward with a low friction member interposed therebetween.

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