JP7348778B2 - Vertical roller mill - Google Patents

Description

The present invention uses a structure of a raw material chute provided in a vertical roller mill.

Vertical roller mills have conventionally been used to crush solid fuels such as coal and cement raw materials such as limestone and clay. Patent Documents 1 and 2 disclose this type of vertical roller mill.

The vertical roller mill (vertical crusher) of Patent Document 1 includes a rotary table, a plurality of rotatable crushing rollers arranged on the upper surface of the outer periphery of the rotary table, and a raw material input chute suspended directly above the center of the rotary table. Equipped with. Then, the raw material supplied onto the rotary table via the raw material input chute is caught between the rotary table and the circumferential surface of the crushing roller and is crushed.

In the above-mentioned vertical roller mill, depending on the nature of the raw material being input, the raw material fed into the raw material input chute adheres to the inner surface of the chute and solidifies, which grows and narrows or blocks the passage inside the chute. This may hinder the smooth supply of raw materials.

To solve this problem, in Patent Document 1, the raw material input chute is made of an inner and outer double pipe, a plurality of ventilation holes are provided in the inner wall of the inner pipe, and compressed air or compressed water is provided between the inner pipe and the outer pipe. is supplied. This prevents the raw material from adhering to the inner wall of the chute due to the compressed air or compressed water blown out from the inner wall of the chute.

Further, in Patent Document 2, a water injection hole is provided at the upper part of a raw material input chute (coal feed pipe), and water is supplied to the water injection hole via an injection pump and a water injection valve. The water flowing down the inner wall surface of the raw material input chute prevents the raw material from adhering to the inner wall of the chute.

Japanese Patent Application Publication No. 4-171051 Japanese Patent Application Publication No. 5-269394

The raw material input chute of the vertical roller mills disclosed in Patent Documents 1 and 2 is referred to as a "center chute type." On the other hand, there is a vertical roller mill called a "side chute type" which is equipped with a raw material input chute that is inclined with respect to the vertical. Compared to the center chute type, the side chute type raw material input chute has advantages such as being easily compatible with large vertical roller mills and reducing initial costs. However, the side chute type raw material input chute has a problem in that the raw material tends to adhere to the inner wall of the chute compared to the center chute type.

The present invention has been made in view of the above circumstances, and its purpose is to effectively suppress the adhesion of raw materials to the inner wall of the chute in a vertical roller mill equipped with a side chute type raw material input chute.

The vertical roller mill according to one aspect of the present invention is
rotating table and
a plurality of crushing rollers arranged on the top surface of the rotary table;
A chute body extending along a chute axis inclined from the vertical, a plurality of nozzles for spouting pressurized water into the chute body, and a water supply pressure pump for feeding the pressurized water to the plurality of nozzles, and onto the rotary table. A raw material input chute for supplying the raw material to be crushed;
The plurality of nozzles are arranged on each side of the chute body in the width direction,
Each of the plurality of nozzles has a nozzle axis tilted downward from the horizontal in a cross section of the chute body, and spouts the pressurized water toward an inner wall of the chute body along the nozzle axis;
At least one of the plurality of nozzles is a fan-shaped nozzle in which the outer edge of the jet of pressurized water spreads in a fan shape around the nozzle axis, and the fan-shaped nozzle has an elliptical or rectangular nozzle, and the nozzle has an oval or rectangular nozzle. The chute body has a first end and a second end, and the height of one of the first end and the second end located on the downstream side from the bottom surface of the chute body in a direction perpendicular to the chute axis. The height is smaller than the height from the bottom surface of the other chute body in a direction perpendicular to the chute axis.

In the vertical roller mill configured as described above, pressurized water is ejected from the plurality of nozzles toward the inner wall of the chute body. When pressurized water collides with raw material that has adhered to (or is about to adhere to) the inner wall of the chute, the impact scrapes the layer of raw material from the surface or causes water to enter beneath the layer of raw material from the inner wall of the chute that is exposed between the raw materials. As a result, the raw material peels off from the inner wall of the chute. The raw material separated from the inner wall of the chute flows down the chute body due to its own weight and/or due to the action of running water. Thus, according to the above configuration, in a vertical roller mill equipped with a side chute-type raw material input chute, it is possible to suppress the adhesion of raw materials to the inner wall of the chute.

According to the present invention, in a vertical roller mill equipped with a side chute-type raw material input chute, it is possible to effectively suppress the adhesion of raw materials to the inner wall of the chute.

FIG. 1 is a diagram showing a schematic configuration of a vertical roller mill according to an embodiment of the present invention. FIG. 2 is an enlarged view of the raw material input chute shown in FIG. FIG. 3 is a cross-sectional view taken along line III--III in FIG. FIG. 4 is a sectional view taken along the line IV-IV in FIG. FIG. 5 is a perspective view of the raw material input chute seen through the chute cover. FIG. 6 is a view of the raw material inputting chute that has passed through the chute cover, viewed from above perpendicular to the chute axis. FIG. 7 is a cross-sectional view of the material inputting chute through the chute cover. FIG. 8 is a front view of the nozzle surface of the nozzle. FIG. 9 is a model of the nozzle jet direction in the verification test.

Next, embodiments of the present invention will be described with reference to the drawings.

[Schematic configuration of vertical roller mill 1]
FIG. 1 is a diagram showing a schematic configuration of a vertical roller mill 1 according to an embodiment of the present invention. As shown in FIG. 1, the vertical roller mill 1 includes a rotary table 2 to which the raw material to be crushed is supplied to the central part of its upper surface, and a plurality of crushing rollers 3 that bite and crush the raw material between the rotary table 2 and the rotary table 2. Equipped with. The rotary table 2 and the plurality of grinding rollers 3 are covered by a mill casing 7.

The rotary table 2 is rotationally driven by a table driving device 5 around a vertical axis of rotation passing through the center of the rotary table 2 . The table drive device 5 includes a mill motor 51, a speed reducer 52 that amplifies the rotational torque of the mill motor 51, and transmits the amplified torque to the rotary table 2.

The plurality of crushing rollers 3 are arranged at equal angular intervals on a circumferential orbit centered on the rotational axis of the rotary table 2. In FIG. 1, one of the plurality of crushing rollers 3 is illustrated. Each of the plurality of crushing rollers 3 is elastically pressed toward the rotary table 2 by a roller pressing device 4 equipped with a drive source such as a hydraulic cylinder.

A funnel-shaped inner cone 11 is provided above the rotary table 2. The outlet of the inner cone 11 is located above the center of the rotary table 2. A separator 9 is provided inside the mill casing 7 and above the inner cone 11 . A raw material input chute 8 for feeding the raw material to be crushed onto the rotary table 2 is provided. The raw material input chute 8 is a side chute type that penetrates the side of the mill casing 7. A feeder 14 quantitatively supplies raw materials to the entrance of the raw material input chute 8 .

The separator 9 includes, for example, a classification rotor 91, a classification vane 92 provided on the outer peripheral side of the classification rotor 91, a separator drive device 93 that rotationally drives the classification rotor 91, and the like.

A mill outlet 71 is formed above the rotary table 2 and separator 9 in the mill casing 7 . The exhaust passage 31 is connected to the mill outlet 71 , and the mill exhaust flows out from the mill outlet 71 to the exhaust passage 31 . The exhaust path 31 is provided with a collection device 33 that collects crushed materials accompanying the mill exhaust. The collection device 33 may be, for example, a bag filter or a cyclone. Further, the exhaust path 31 is provided with an exhaust fan 34 . By changing the rotation speed of this exhaust fan, the flow rate of mill exhaust gas discharged from the mill outlet 71 can be adjusted.

A hot gas outlet 73 having an annular shape or arranged in an annular shape is provided between the outer peripheral edge of the rotary table 2 and the mill casing 7. A hot gas source is connected to a hot air inlet 72 provided below the rotary table 2 of the mill casing 7 via piping or the like. The hot gas supplied from the hot gas source to the hot air inlet 72 is blown upward from the hot gas outlet 73.

In the vertical roller mill 1 having the above configuration, when the feeder 14 supplies the raw material to be crushed (for example, slag, etc.) to the raw material input chute 8, the raw material is supplied to the center of rotation of the rotary table 2 through the raw material input chute 8. be done. The raw material supplied onto the rotary table 2 is moved radially outward by the centrifugal force accompanying the rotation of the rotary table 2, and the raw material is moved radially outward by the centrifugal force caused by the rotation of the rotary table 2, and the raw material is moved between the crushing roller 3, which is driven by the rotation of the rotary table 2, and the rotary table 2. It gets caught in between and shatters.

The pulverized material is moved toward the outer edge of the rotary table 2 by centrifugal force, dried by the hot gas blown up from the hot gas outlet 73 around the rotary table 2, and is carried upward by airflow. Incidentally, spillage such as crushed materials, gravel, and metal pieces that do not ride on the hot gas airflow falls from the outer peripheral edge of the rotary table 2 due to centrifugal force, and is collected in a collection box 76 provided below and on the outer peripheral side of the rotary table 2. will be collected.

The pulverized material blown up by the hot gas passes between the fixed blades of the classification vane 92 and then between the rotary blades of the classification rotor 91, thereby separating powder particles coarser than the desired particle size (particle size) and finer particles. It is classified into powder and granules. The fine powder particles classified by the separator 9 are discharged to the outside of the machine through the mill outlet 71 along with the exhaust gas from the mill casing 7. The mill exhaust gas flowing out from the mill outlet 71 to the exhaust path 31 passes through a collection device 33 to separate fine particles (fine powder). The separated fine powder is recovered as a product. On the other hand, the coarse powder particles classified by the separator 9 slide down the inner cone 11 and are returned onto the rotary table 2, where they are crushed again together with the raw material supplied through the raw material input chute 8.

[Configuration of raw material input chute 8]
In the vertical roller mill 1 according to this embodiment, the raw material introduced into the raw material input chute 8 has high adhesion. Therefore, the raw material input chute 8 is equipped with a mechanism to prevent the attachment of raw materials and the blockage caused by the adhesion of raw materials. The configuration of the raw material input chute 8 will be described in detail below.

FIG. 2 is an enlarged view of the raw material input chute 8 shown in FIG. The raw material input chute 8 shown in FIG. 2 includes a chute body 81, a chute cover 82, a water sprinkling pipe 83, a plurality of nozzles 84, and a water supply pressure pump 85 that sends pressurized water to the water sprinkling pipe 83.

A chute axis A1 is defined in the raw material input chute 8. The chute body 81 according to this embodiment has a lower semi-cylindrical shape extending parallel to the chute axis A1. The cross section of the chute body 81 is a lower semicircle, and the chute axis A1 passes through the lowest part of the lower semicircle, which corresponds to the bottom of the chute body 81.

The chute axis A1 has an inclination in the range of 50° to 70° from the horizontal. The inclination of the chute axis A1 of the raw material input chute 8 shown in FIGS. 1 and 2 is approximately 60° from the horizontal. The inclination of the chute axis A1 may be determined depending on the properties of the raw material.

The chute body 81 passes through the side of the mill casing 7, and the upper part of the chute body 81 is exposed to the side of the mill casing 7. The upper part of this chute body 81 is connected to the lower part of the hopper 15 provided below the feeder 14. Raw materials quantitatively supplied to the hopper 15 by the feeder 14 are sequentially introduced into the chute body 81 through the hopper 15.

The lower part of the chute body 81 is inserted into the mill casing 7. The lower end of the chute body 81 is located near the outlet of the inner cone 11, that is, above the center of the rotary table 2. Inside the mill casing 7, the chute body 81 is exposed to an upward air current. Therefore, in order to avoid contact between the raw material flowing down the chute body 81 and the rising air current, a chute cover 82 is provided on the chute body 81. When assembling or maintaining the chute body 81, the chute cover 82 can be removed from the chute body 81.

FIG. 3 is a cross-sectional view taken along line III--III in FIG. As shown in FIG. 3, in the mill casing 7, a chute cover 82 (a first chute cover 82a) is provided. The first chute cover 82a is an upper semi-cylindrical member that covers the upper side of the chute body 81.

FIG. 4 is a sectional view taken along the line IV-IV in FIG. As shown in FIG. 4, in the mill casing 7, a chute cover 82 (second chute cover 82b) is provided in the gap between the inner cone 11 and the chute body 81 to close the gap. The second chute cover 82b is a plate-shaped member that forms a wall that extends the side wall of the chute body 81 upward.

FIG. 5 is a perspective view of the raw material inputting chute 8 passing through the chute cover 82, and FIG. 6 is a view of the raw material inputting chute 8 passing through the chute cover 82, viewed from above perpendicular to the chute axis A1. As shown in FIGS. 5 and 6, a pair of water sprinkling pipes 83 (a first water sprinkling pipe 83a and a second water sprinkling pipe 83b) are provided on the inner peripheral side of the chute body 81. Each water sprinkling pipe 83 extends parallel to the chute axis A1.

The first water sprinkling pipe 83a and the second water sprinkling pipe 83b are arranged on both sides of the chute body 81 in the width direction. Each water sprinkling pipe 83 is provided with a plurality of nozzles 84 arranged parallel to the chute axis A1 at a predetermined nozzle pitch. The plurality of nozzles 84 are provided at a higher position from the bottom surface 81b of the chute body 81 than the surface of the raw material moving through the chute body 81. Thereby, water can be sprayed from the nozzle 84 onto the surface of the raw material. In this embodiment, the bottom surface 81b of the chute body 81 is a plane including the chute axis A1 and a horizontal line orthogonal to the chute axis A1.

The nozzles 84 provided in the first water sprinkling pipe 83a and the nozzles 84 provided in the second water sprinkling pipe 83b are arranged alternately along the chute axis A1. In other words, the plurality of nozzles 84 are distributed on both sides of the chute body 81 in the width direction, and are arranged in a staggered manner along the chute axis A1. The nozzle pitch is desirably determined so that the water sprinkling range S of the nozzle 84 does not overlap with the water sprinkling range S of other nozzles 84 .

A water supply pressure pump 85 is connected to each water sprinkling pipe 83 via a pipe, tube, or the like. Pressurized water is sent from the water supply pressure pump 85 to each water sprinkling pipe 83 . The pressurized water sent to the water sprinkling pipe 83 is ejected from the nozzle 84 along the nozzle axis A2. A nozzle axis A2 is defined for each nozzle 84.

The nozzle 84 may be a so-called fan-shaped nozzle. The nozzle 841 (see FIG. 8) of the nozzle 84 has an elliptical or rectangular shape with a longitudinal direction A3 orthogonal to the nozzle axis A2. The outer edge of the jet of pressurized water spouted from this spout 841 spreads in a fan shape on both sides with the nozzle axis A2 as the center of symmetry. The spray angle of the nozzle 84 is 90° or more, preferably 115° or more. Note that the plurality of nozzles 84 have substantially the same aspect.

A connecting portion 86 between the water sprinkling pipe 83 and the nozzle 84 includes a ball joint. Thereby, the extending direction of the nozzle axis A2 of the nozzle 84 is variable. The extending direction of each nozzle axis A2 is appropriately adjusted as described below. However, the connecting portion 86 of the nozzle 84 may remain unchanged, and the extending direction of the nozzle axis A2 may be fixed.

As shown in FIG. 6, the nozzle axis A2 is inclined downstream from the cross section C of the chute body 81 along the chute axis A1 at a first inclination angle θ1. Note that in this specification, the term "cross section of the chute body 81" refers to a cross section of the chute body 81 perpendicular to the chute axis A1. Moreover, the "upstream side" is defined as the side corresponding to the upstream side of the flow of the raw material moving along the chute axis A1, of both sides of the chute axis A1 in the extending direction. Moreover, the "downstream side" is defined as the side opposite to the upstream side among both sides of the chute axis A1 in the extending direction.

The first inclination angle θ1 is 0° or more and 90° or less, preferably 20° or more and 50° or less. In the example shown in FIG. 6, the first inclination angle θ1 is approximately 30°. The first inclination angle θ1 is desirably determined so that the water sprinkling range S of the nozzle 84 includes a larger area of the chute inner wall 81a that comes into contact with the raw material. Furthermore, it is desirable that the first inclination angle θ1 is determined such that the upstream end of the watering range S of each nozzle 84 is below the cross section of the nozzle 84 that includes the connecting portion 86.

FIG. 7 is a cross-sectional view of the raw material input chute 8. As shown in FIG. 7, in the cross section of the raw material input chute 8, the nozzle axis A2 of the nozzle 84 is inclined downward from the horizontal plane at a second inclination angle θ2. The second inclination angle θ2 is greater than 0° and less than or equal to 90°, preferably greater than or equal to 20° and less than or equal to 50°. In the example shown in FIG. 7, the second inclination angle θ2 is approximately 45°.

FIG. 8 is a front view of a nozzle surface 840 in which a nozzle 841 is formed in the nozzle 84. As shown in FIG. 8, a V-shaped notch 842 is formed in the nozzle surface 840. A nozzle 841 is formed in the center of the notch 842. The valley line of the cut 842 and the longitudinal direction A3 of the nozzle 841 are parallel. The spout 841 has a first end 845 and a second end 846 in the longitudinal direction A3. The height from the first end 845 and the bottom surface 81b of the chute body 81 in a direction perpendicular to the chute axis A1 is defined as H1. The height from the second end 846 and the bottom surface 81b of the chute body 81 in a direction perpendicular to the chute axis A1 is defined as H2.

In FIG. 8, of the first end 845 and the second end 846, the first end 845 is located on the downstream side. Further, the height H1 is smaller than the height H2. In other words, the longitudinal direction A3 of the spout 841 is inclined at the third inclination angle θ3 with respect to the bottom surface 81b of the chute body 81 so that the downstream side is lower and the upstream side is higher. The third inclination angle θ3 is greater than 0° and less than or equal to 90°, preferably greater than or equal to 10° and less than or equal to 45°. In the example shown in FIG. 8, the third inclination angle θ3 is approximately 20°.

[Verification test of raw material adhesion suppression effect]
A verification test was conducted to verify the effect of water sprinkling on material adhesion inhibition in the material input chute 8 having the above configuration. The configuration of the mock chute used in the verification test and the test method are as follows.

(Mock shoot)
The chute body 81 of the simulated chute has a lower semi-cylindrical shape with a diameter of 550 mm and a length of 2 m. Water sprinkling pipes 83 are distributed on both sides of the chute body 81 in the width direction, and nozzles 84 are attached to each water sprinkling pipe 83 at two locations. The nozzle pitch in each water sprinkling pipe 83 is 1000 mm. A total of four nozzles 84 are arranged in a staggered manner along the length direction of the chute body 81 (that is, the direction in which the chute axis A1 extends).

(Verification test method)
1) Mix slag, gypsum, crushed products, and water to create a simulated raw material. The blending ratio of slag:gypsum:pulverized product:water is 10:20:30:9 in terms of mass ratio.
2) The same mass of simulated raw material is evenly deposited on the inner surface of each simulated chute. Here, the simulated chute is placed in a position where its length direction is substantially horizontal, and the simulated raw material is pressed and adhered to the inner surface of the chute.
3) Set the simulated chute in a posture where its length direction is inclined by 60 degrees from the horizontal, and start watering under predetermined watering conditions (watering amount, supply water pressure, and nozzle jet direction). The watering conditions for Examples 1 to 13 are shown in Table 1 below. However, in Example 1, water at a predetermined supply water pressure is allowed to fall naturally from the top of the simulated chute at a flow rate corresponding to a predetermined nozzle water sprinkling amount. In Example 2, no nozzle is attached to the water sprinkling pipe 83 of the simulated chute, and water at a predetermined supply water pressure is allowed to fall naturally from a hole provided in the water sprinkling pipe 83 at a flow rate corresponding to a predetermined nozzle water sprinkling amount.
4) Measure the time required for 90% by mass of the simulated raw material attached to the simulated chute to fall after starting watering (hereinafter referred to as "falling time"). If the time required to fall exceeds 300 seconds, a timeout will occur. Additionally, during the test, the state of water splashing and the progress of peeling of the simulated raw material will be observed.
5) Evaluate the effect of suppressing material adhesion based on the time required for falling.

In Table 1, the nozzle water sprinkling amount is the amount of pressurized water [m ³ /h] ejected from each nozzle 84. The supply water pressure is the pressure [kg/cm ² ] of pressurized water that is force-fed to the nozzle 84. The nozzle rated flow rate represents the jetting amount when the nozzle 84 has a standard pressure (3 kg/cm ² ). The nozzle injection direction can be specified by the first inclination angle θ1 (see FIG. 6) and the second inclination angle θ2 (see FIG. 7). FIG. 9 is a model of the nozzle jet direction in the verification test. In model T1 shown in FIG. 9, θ1=30° and θ2=45°, and water is ejected from the nozzle 84 toward the downstream side of the simulated chute. In model T2, θ1=0° and θ2=45°, and water is ejected from the nozzle 84 toward the center in the width direction of the simulated chute. In model T3, θ1=0° and θ2=90°, and water is ejected downward from the nozzle 84. The state of water droplets being scattered outside the chute is expressed in five levels, and the higher the number, the greater the amount of water droplets being scattered. The raw material adhesion suppression effect is expressed in three levels, with A being the time required for falling within 100 seconds, B being from 101 seconds to 240 seconds, and C being 241 seconds or more.

In the verification test, the following progression of peeling of the simulated raw material was observed. In the water sprinkling range of the nozzle 84, that is, in the range where the pressurized water spouted from the nozzle 84 and the simulated raw material directly collide, the surface of the adhered layer of the simulated raw material is scraped off by the action of the water, and the scraped simulated raw material is scraped off with the flowing water. run down. When the inner wall 81a of the chute is exposed between the layers of the simulated raw material by being scraped away by the action of water, water sneaks under the layer of the simulated raw material, thereby causing the layer of simulated raw material to collapse and flow down in the form of a lump. . Outside the spraying range of the nozzle 84, that is, in the range where the pressurized water ejected from the nozzle 84 and the simulated raw material do not directly collide, the surface is gradually eroded by natural water flowing from upstream, and the attached simulated raw material flows down.

Furthermore, in the verification test, the following characteristics of the progress of peeling of the simulated raw material for each model were observed. In model T1, compared to model T2, the water sprinkling range S of the nozzle 84 is wider, and the effect of scraping off the attached simulated raw material is greater, and the effect of sweeping the attached simulated raw material downstream is greater. In model T3, the pressurized water does not directly collide with the attached simulated raw material, but the surrounding area of the attached simulated raw material is gradually scraped away by the flowing water.

As shown in Table 1, in the verification test, the effect of suppressing material adhesion was found to be low both when water was flowed down from the upper part of the chute body 81 and when the nozzle 84 was not provided in the water sprinkling pipe 83. It was done. From this, it has become clear that the effect of suppressing material adhesion is improved by causing the pressurized water ejected from the nozzle 84 to collide with the surface of the material adhering to (or about to adhere to) the chute inner wall 81a. .

Further, in the verification test, it was found that the material adhesion suppressing effect was obtained when the amount of water sprayed from the nozzle 84 was 0.17 to 0.25 [m ³ /h]. It is easily assumed that increasing the amount of water sprayed by the nozzle 84 will improve the material adhesion suppressing effect, but if the amount of water sprayed increases, the amount of water supplied to the entire mill will increase, which will increase the heat loss of the entire mill. . The amount of water sprayed by the nozzles 84 can be determined by determining the allowable amount of water supply from the heat balance of the entire mill, and dividing it by the number of nozzles 84 provided in the raw material input chute 8.

Further, in the verification test, it was found that the material adhesion suppressing effect was obtained when the water pressure supplied to the nozzle 84 was 2 [kg/cm ² ] or more and 5 [kg/cm ² ] or less. The value of the water pressure supplied to the nozzle 84 may be greater than 5 [kg/cm ² ], but if it is excessive, it is assumed that the amount of water spray increases and is inefficient.

As described above, the vertical roller mill 1 according to the present embodiment includes a rotary table 2, a plurality of crushing rollers 3 arranged on the upper surface of the rotary table 2, and a raw material to be crushed onto the rotary table 2. A raw material input chute 8 is provided. The raw material input chute 8 has a chute body 81 extending along a chute axis A1 inclined from the vertical, a plurality of nozzles 84 that spout pressurized water into the chute body 81, and a water supply pressure pump 85 that sends pressurized water to the nozzles 84. . The plurality of nozzles 84 are arranged on each of both sides of the chute body 81 in the width direction, and each of the plurality of nozzles 84 has a nozzle axis A2 that is inclined downward from the horizontal in the cross section of the chute body 81. Pressurized water is ejected toward the inner wall of the chute body 81 along the nozzle axis A2.

In the vertical roller mill 1 configured as described above, pressurized water is ejected from the plurality of nozzles 84 toward the inner wall of the chute body 81 (chute inner wall 81a). When pressurized water collides with the raw material that has adhered (or is about to adhere) to the chute inner wall 81a, the impact scrapes the raw material layer from the surface, or the water flows from the chute inner wall 81a exposed between the raw materials below the raw material layer. The raw material may be peeled off from the inner wall 81a of the chute. The raw material separated from the chute inner wall 81a flows down the chute body 81 due to its own weight and/or due to the action of running water. In this way, in the vertical roller mill 1 equipped with the side chute type raw material input chute 8, it is possible to suppress the adhesion of raw materials to the chute inner wall 81a.

Furthermore, in the vertical roller mill 1 described above, the nozzle axis A2 has an inclination toward the downstream side (second inclination angle θ2) along the chute axis A1.

As a result, the flow of pressurized water blown out from the nozzle 84 has a downward component, and the raw material separated from the chute inner wall 81a is effectively swept downstream. This facilitates the falling of the raw material in the chute body 81.

In the vertical roller mill 1 described above, the pressure of the pressurized water jetted from the nozzle 84 may be 2 kg/cm ² or more and 5 kg/cm ² or less. If the pressure of the pressurized water becomes too low, the raw material adhering to the chute inner wall 81a cannot be peeled off. Moreover, if the pressure of the pressurized water becomes excessive, the amount of water that collides with the raw material and the chute inner wall 81a and scatters increases, and the peeling effect is rather reduced. By setting the water pressure of the pressurized water as described above, the raw material adhering to the chute inner wall 81a can be effectively peeled off.

In the vertical roller mill 1 according to the present embodiment, at least one of the plurality of nozzles 84 is a fan-shaped nozzle in which the outer edge of the jet of pressurized water spreads out in a fan shape around the nozzle axis A2.

The fan-shaped nozzle has a wider watering range S than the straight nozzle. Thereby, it is possible to expand the range of the chute inner wall 81a that the pressurized water ejected from the nozzle 84 directly collides with. By causing the pressurized water jetted from the nozzle 84 to directly collide with the raw material adhering to the chute inner wall 81a, the raw material can be effectively peeled off from the chute inner wall 81a, as described above.

The sector-shaped nozzle described above has an oval or rectangular nozzle 841. The spout 841 has a first end 845 and a second end 846 in the longitudinal direction A3. Height H1 from the bottom surface 81b of the chute body 81 of one of the first end 845 and the second end 846 located on the downstream side (the first end 845 in this embodiment) in the direction perpendicular to the chute axis A1 is smaller than the height H2 from the bottom surface 81b of the other chute body 81 (second end 846 in this embodiment) in the direction orthogonal to the chute axis A1.

In this way, the longitudinal direction A3 of the spout 841 of the nozzle 84 has an inclination from the bottom surface 81b of the chute body 81. Thereby, the water sprinkling range S of the nozzle 84 can be expanded using the fan-shaped nozzle.

In the vertical roller mill 1 according to the present embodiment, the raw material input chute 8 further includes water sprinkling pipes 83 disposed on both sides of the chute body 81 in the width direction and extending along the chute axis A1. A plurality of nozzles 84 are arranged in a staggered manner in the pipe 83.

Thereby, water can be sprayed over a wider range of the chute inner wall 81a while suppressing the number of nozzles 84 provided in the raw material inputting chute 8.

Further, the vertical roller mill 1 according to the present embodiment includes a mill casing 7 that accommodates a rotary table 2 and a plurality of crushing rollers 3, a separator 9 disposed above the rotary table 2 in the mill casing 7, and a separator 9. and an inner cone 11 disposed between the rotary table 2 and the rotary table 2. The chute body 81 has a lower semi-cylindrical shape, and at least a portion of the chute body 81 is inserted into the mill casing 7. In the mill casing 7, a chute cover 82 that closes at least one of the gap between the chute body 81 and the inner cone 11 and the gap between the chute body 81 and the separator 9 is removably attached to the chute body 81. It is provided.

Such a chute cover 82 makes it possible to avoid contact between the raw material flowing down the raw material input chute 8 and the rising air current within the mill casing 7 .

Although the preferred embodiments of the present invention have been described above, the present invention may include modifications to the specific structure and/or functional details of the above embodiments without departing from the spirit of the present invention. . The above configuration can be modified as follows, for example.

For example, in this embodiment, the chute body 81 has a lower semi-cylindrical shape, but the shape of the chute body 81 is not limited to this embodiment. The chute body 81 may be in the shape of a gutter through which the raw material can flow.

1: Vertical roller mill 2: Rotary table 3: Grinding roller 4: Roller pressing device 5: Table drive device 7: Mill casing 8: Raw material input chute 9: Separator 11: Inner cone 14: Feeder 15: Hopper 31: Exhaust path 33 : Collection device 34 : Exhaust fan 51 : Mill motor 52 : Reducer 71 : Mill outlet 72 : Hot air inlet 73 : Hot gas outlet 76 : Collection box 81 : Chute body 81a : Chute inner wall 81b : Bottom surface 82 : Chute cover 83 : Water sprinkling pipe 84 : Nozzle 85 : Water supply pressure pump 86 : Connection part 91 : Classifying rotor 92 : Classifying vane 93 : Separator drive device 840 : Nozzle surface 841 : Spout 842 : Notch 845 : First end 846 : Second end Part A1: Chute axis A2: Nozzle axis A3: Longitudinal direction

Claims (5)

rotating table and
a plurality of crushing rollers arranged on the top surface of the rotary table;
A chute body extending along a chute axis inclined from the vertical, a plurality of nozzles for spouting pressurized water into the chute body, and a water supply pressure pump for feeding the pressurized water to the plurality of nozzles, and onto the rotary table. A raw material input chute for supplying the raw material to be crushed;
The plurality of nozzles are arranged on each side of the chute body in the width direction,
Each of the plurality of nozzles has a nozzle axis tilted downward from the horizontal in a cross section of the chute body, and spouts the pressurized water toward an inner wall of the chute body along the nozzle axis;
At least one of the plurality of nozzles is a fan-shaped nozzle in which the outer edge of the jet of pressurized water spreads in a fan shape around the nozzle axis, and the fan-shaped nozzle has an elliptical or rectangular nozzle, and the nozzle has an oval or rectangular nozzle. The chute body has a first end and a second end, and the height of one of the first end and the second end located on the downstream side from the bottom surface of the chute body in a direction perpendicular to the chute axis. is smaller than the height from the bottom of the other chute body in a direction perpendicular to the chute axis;
Vertical roller mill. The nozzle axis has an inclination toward the downstream side along the chute axis,
The vertical roller mill according to claim 1. The raw material input chute further includes water sprinkling pipes arranged on each side of the chute body in the width direction and extending along the chute axis,
the plurality of nozzles are arranged in a staggered manner in the watering pipe;
The vertical roller mill according to claim 1 or 2 . The pressure of the pressurized water ejected from the plurality of nozzles is 2 kg/cm ² or more and 5 kg/cm ² or less,
The vertical roller mill according to any one of claims 1 to 3 . a mill casing that accommodates the rotary table and the plurality of grinding rollers; a separator disposed above the rotary table within the mill casing; and an inner cone disposed between the separator and the rotary table. , further prepare,
The chute body has a lower semi-cylindrical shape,
at least a portion of the chute body is inserted within the mill casing;
In the mill casing, a cover that closes at least one of a gap between the chute body and the inner cone and a gap between the chute body and the separator is removably provided with respect to the chute body. ,
The vertical roller mill according to any one of claims 1 to 4 .

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