JP2012125759A - Crushing face member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a crushing face member which is effective in pulverization of a raw material to be pulverized having large adherability and/or viscosity such as limestone and in power cost reduction.SOLUTION: Raw material biting grooves 11 intersecting a moving direction are provided at prescribed intervals in the moving direction, at a pulverizing roller 10 or a rotary table in a vertical roller mill or at a pulverizing roller or a raw material crushing face 12 of a bull ring in a centrifugal roller mill. A cross-sectional shape of each groove 11 is made to be a wedge shape, in which an inside surface on a downstream side in the moving direction is inclined onto the downstream side in the moving direction. Preferably the wedge shape groove 11 is formed at one surface of the pulverizing roller 10 or the rotary table, or at one surface of the pulverizing roller or the bull ring in the centrifugal roller mill, and the other surface is made smooth.

Description

  The present invention relates to a crushing surface member that directly contributes to the crushing of a crushing raw material such as a crushing roller and a table in a vertical roller mill or a crushing roller and a bull ring in a centrifugal roller mill, and more specifically, adherence like limestone. In addition, the present invention relates to a crushing surface member that is effective for pulverization of a pulverized raw material having high adhesiveness and for reducing power cost.

  It is no exaggeration to say that limestone mine is the only remaining mining industry in Japan. Limestone is a mineral resource that is widely distributed in Japan and produced in large quantities. However, market prices for quicklime, slaked lime, calcium carbonate, etc. have been sluggish and demand has been sluggish.Further, the price of heavy oil has soared that lime producers are in a difficult situation to secure profits. Guessed.

  A large number of vertical roller mills are used for pulverization of limestone. However, many centrifugal roller mills have been used in the past before the vertical roller mills became widespread, and they continue to be used today. The vertical roller mill includes driven crushing rollers disposed at a plurality of locations in the circumferential direction on the rotary table, and the crushing raw material supplied to the central portion of the rotary table is mixed with the table along with the rotation of the rotary table. By crushing into a clearance set between the pulverization rollers, the pulverized raw material is pulverized by rollers.

  On the other hand, the centrifugal roller mill includes a plurality of horizontal rollers that are suspended and supported so as to be able to tilt in a radial direction on a plurality of arms extending radially from a vertical rotation shaft provided at a central portion in a cylindrical housing. And a bull ring (starting wheel) mounted on the inner surface of the housing and positioned on the outer peripheral side of the crushing roller, and a plurality of crushing rollers bull like pendulums by the centrifugal force accompanying the rotation of the rotating shaft. While being pressed against the ring and driven to rotate, at that time, the pulverized raw material is caught between the pulverizing roller and the bull ring, whereby the pulverized raw material is roller-pulverized. Centrifugal roller mills are also called Raymond mills and ring roll mills, and the main reason why they continue to be used is for limestone, especially tankal grinding, because the ground material is not hard enough to cause roller and ring wear for 10 years. The mill is in a situation where it can be used continuously for 15 years.

  Improving the production of fine powder of limestone, especially Tankar, with such vertical roller mills and centrifugal roller mills, especially those large machines, is one of the most important technical issues, but it is a major problem in limestone grinding. The point is the production cost. Among them, the power consumption cost required for pulverization is considered to occupy a particularly large position among the economic factors.

  Against this backdrop, the present inventor has developed a technique relating to a crushing surface combination of a roller and a table that can suppress the vibration of the mill by increasing the amount of fine powder pulverization with a vertical roller mill that crushes adhesive substances, particularly limestone. Presented earlier in US Pat.

  Limestone becomes fine powder as it is crushed, and adhesion and adhesion become remarkable. And if there is much moisture, the tendency will be further encouraged. This trend does not change even in the current pulverizing mill, and limestone adheres and adheres to the pulverizing roller and the table surface, making the pulverization operation difficult, and vibration may be generated to interrupt the pulverization operation. The feature of the technology presented by Patent Document 1 is that, firstly, screw grooves are formed on the roller grinding surface to prevent the adhesion of limestone, and the limestone introduced into the center of the mill is used as the main roller diameter side. Secondly, the table crushing surface is formed with slit grooves in the direction perpendicular to the table rotation direction to improve the biting performance.

  When crushing the adhesive substance, if a slit groove perpendicular to the rotation direction or a slit groove having an angle of up to 45 degrees with respect to the perpendicular direction is formed on the roller grinding surface, the slit groove scoops up the limestone, and the roller In order to promote the adhesion of limestone to the surface, it is impossible to attach a slit groove for improving this kind of biting property to the surface of the grinding roller. Therefore, a screw-like groove that does not scrape limestone is formed on the roller grinding surface, the limestone is transported while preventing adhesion, and a right-angle slit groove that improves the biting property is attached to the table. . The biting performance of the table is inferior to the biting performance exhibited by the rotational force of the roller because the table rotates horizontally, but contributes to the improvement of productivity. This combination of crushing surfaces contributes to reducing the power cost of the mill.

  The clearance between the roller and the table is initially set to a distance including the clearance required for crushing, including the thickness of the limestone that has quantitatively adhered to the surfaces of both. When the amount of water contained in the limestone increases, the amount attached to the roller and the table increases, and the clearance cannot be maintained in a constant state. Therefore, the preset stable clearance becomes too narrow, and limestone is forcibly bitten into the gap, so that a very large resistance load is generated and the axial current of the mill increases. If this situation continues for a long time, the waste of the power cost becomes very large, which increases the production cost. In the worst case, a predetermined production amount cannot be obtained or a choke state occurs, and limestone is discharged, leading to mill stoppage. In addition, a large vibration is generated in the mill, and the operation is interrupted because the vehicle is out of the steady state.

  On the other hand, when the screw groove is formed on the roller outer peripheral surface in the direction in which limestone is actively fed to the outer peripheral side of the table, the limestone is stably fed to the main grinding surface on the roller large-diameter side, and the forced feeding action is performed. A stable crushing operation is possible compared to a smooth surface roller that does not have it. Moreover, due to the effect of the right-angle slit grooves formed on the table surface, the pulverization amount and fineness are improved, and the power consumption is reduced. However, the screw groove formed on the roller is excellent in the effect of forcibly conveying limestone, but lacks the ability to remove limestone that has adhered excessively on the table. If the ability to always remove excess limestone is always excellent, the resistance load will be reduced, the power consumption of the mill will be reduced, and the amount of pulverized powder will be increased, which will greatly contribute to the reduction in power intensity. Is assumed.

  As a grinding roller in a vertical roller mill, there are 1) a trapezoidal roller and 2) a tire-type roller. The main pulverization surface of these rollers exists on the large diameter side in the trapezoidal type roller, and in the convex type roller of D / R ≧ 4.3, the tire type roller exists in the center of the tire, and D / R < In the 4.3 type flat roller, it exists in the small diameter part on both sides. Here, D is the maximum diameter of the grinding roller, and R is the radius of curvature in a plane perpendicular to the rotation direction of the tire crushing surface.

  As described above, in the crushing roller in the vertical roller mill, the position of the main crushing surface differs depending on the roller shape. Therefore, in any type of mill roller, in the case of a crushing raw material that easily causes adhesion and adhesion like limestone, a screw In addition to the screw transfer effect of reliably feeding the raw material to the main pulverizing portion of the roller by the groove, the action of removing the excessively pulverized raw material adhered on the table is also important.

JP 2009-142809 A

  The object of the present invention is excellent in the ability to feed the pulverized raw material to the main pulverizing part in large pulverizing mills such as vertical roller mills and centrifugal roller mills, and also excellent in the ability to eliminate pulverized raw materials adhering to and staying in the main pulverizing part. There is a need to provide a crushing surface member that can reduce the power consumption of the mill and thus reduce the crushing cost.

  As one of the methods that can contribute to the reduction of the production cost of fine powder of pulverized raw materials that are liable to adhere and adhere like limestone, especially tancal, the present inventor Research was planned on the possibility of reducing the cost, that is, the power consumption, by giving the crushing mill rollers and tables a unique crushing surface shape. Furthermore, a simple change in the shape of the pulverized surface leads to a reduction in the basic unit of electric power, and it can be expected to contribute significantly to the reduction of carbon dioxide emissions that the lime industry is working on.

  From such a viewpoint, as a result of further various experimental studies, the inventor combined with the technique presented in Patent Document 1 and the like, and more specifically, a crushing surface shape that can greatly reduce power consumption, more specifically, The slit groove shape on the crushing surface, especially its cross-sectional shape, was found. The details are as follows.

  The main effect of the screw groove formed on the crushing roller in the vertical roller mill is to send limestone to the main crushing part of the roller, but in order to make the effect more effective, the edge of the screw groove is on the table. It is very important to cut the excess limestone layer existing in the slab and forcibly discharge it backward in the roller rotation direction.

  A screw groove having a wedge-shaped (le-shaped) cross section for forcibly scraping limestone is effective as the means. Looking at the cross-sectional shape of the screw groove, the rear edge in the roller rotation direction has a sharp edge shape, and the bottom surface of the groove has a gentle taper toward the front edge in the rotation direction to reduce the groove depth. Is flush with the roller crushing surface. The cross section of the screw groove so far has been concave and U-shaped, and in such a groove cross section, the limestone fills the groove immediately after the start of pulverization, and it is not discharged from the groove even by high-speed classification air, and is fixed. There was a tendency to halve the conveying effect and the cutting effect due to the groove edge by filling the groove.

  However, in the case of a screw groove with a wedge-shaped (le-shaped) cross section, the rear edge actively scrapes the limestone that is about to bite in right now or the extra limestone that has adhered to the table due to increased moisture, The scraped limestone is once stored in the wedge-shaped groove and then forcibly discharged to the crushing surface via the tapered surface and the front edge. The wedge-shaped groove is easy to adhere and can easily discharge limestone or the like that easily adheres from the inside of the groove with as little resistance as possible.

  As will be described in detail later, a wedge-shaped groove having a letter-shaped cross section on the crushing surface is also effective for a grinding roller and a pull ring in a centrifugal roller mill.

  The crushing surface member of the present invention has been completed on the basis of such knowledge, and in the crushing surface member that crushes by crushing the pulverized raw material between its surfaces by the synchronous movement of the opposing surface, the direction of motion on the material crushing surface Raw material biting grooves intersecting with respect to each other, that is, slit grooves are provided at predetermined intervals in the movement direction, and the cross-sectional shape of each groove is such that the inner side surface on the downstream side in the movement direction (front side) is the upstream side in the movement direction (front side). The wedge shape is inclined forward.

  In the crushing surface member of the present invention, among the inner surfaces of the slit groove, the inner surface on the downstream side in the movement direction (front side) is inclined forward to the downstream side in the movement direction (front side). The edge of the side), that is, the rear edge, functions as a pulverized raw material scraper that adheres to the opposing crushing surface member. The pulverized raw material scraped off at the rear edge is smoothly discharged without accumulating in the groove because the inner surface on the downstream side (front side) in the movement direction is inclined forward to the downstream side (front side) in the movement direction. . Raw material with strong adhesion and stickiness like limestone due to material scraping and promotion of material discharge due to the inner side of the downstream side (front side) in the direction of motion leaning forward toward the downstream side (front side) in the direction of motion Increases grinding efficiency.

  In fact, in the experiment by the present inventor, limestone that is easy to adhere was pulverized, but the result greatly contributes to the reduction of the power consumption by improving the pulverization amount of the fine powder and reducing the power consumption of the mill. Met.

  The kind of crushing surface member of this invention is not ask | required. This is effective for all slit grooves formed on the pulverizing surface of the crushing surface member, but is particularly effective for the pulverizing roller or rotary table in the vertical roller mill, or the pulverizing roller or pull ring in the centrifugal roller mill. The kind of slit groove in these crushing surface members is not limited.

  In the crushing roller of the vertical roller mill, a screw groove that has a large effect of feeding the raw material to the main crushing part is preferable in consideration of limestone crushing. Similarly, the slit groove in the rotary table is not limited to any kind, but a right-angle groove excellent in crushing ability, that is, a radial groove perpendicular to the rotation direction is desirable, and a screw groove inclined in the raw material discharge direction is also preferable. In any case, when a slit groove is provided on the crushing surface of the crushing roller, the crushing surface of the rotary table is preferably a smooth surface, and when the crushing surface of the crushing roller is a smooth surface, a slit groove is formed on the crushing surface of the rotary table. Is preferably provided.

  In the rotary table in the vertical roller mill, the outer peripheral surface is a crushing surface. The outer peripheral portion of the annular crushing surface is a main crushing surface, and the crushing surface on the inner peripheral side is a raw material scraping surface. Usually, the slit groove is provided on the entire crushing surface. However, it is also effective to provide the main crushing surface as a flat surface and to provide the slit groove on the raw material scraping surface on the inner peripheral side. The area of the main crushing surface is 30 to 40% in the length ratio in the radial direction of the entire annular crushing surface.

  In the centrifugal roller mill, a grinding roller composed of 3 to 6 horizontal rollers is tilted to the outer peripheral side by a pendulum motion along the inner peripheral surface of the bull ring, and is sandwiched between the inner peripheral surface of the bull ring and the roller. The pulverization principle is to pulverize the pulverized raw material with the pressing pressure and frictional force caused by the centrifugal force. Therefore, unlike the vertical roller mill, there is no preset gap between the pulverizing roller and the rotary table, and a layer thickness of the pulverized material is generated between the inner peripheral surface of the bull ring and the pulverizing roller. The pulverized raw material is continuously scraped up from below by a plow rotating together with the rotating shaft, and is forcedly supplied between the inner peripheral surface of the bull ring and the pulverizing roller to promote pulverization.

  As can be seen from this, when pulverizing a material that tends to adhere, such as limestone, the thickness of the material layer formed on the pulverized surface is naturally determined even if adhesion occurs on the grinding roller or bull ring. A crusher that does not require artificial initial setting is a centrifugal roller mill. For example, if it is assumed that a large amount of tancal adheres to the pulverizing roller mill and the bull ring, it is naturally estimated that the gap between the two becomes larger than when no raw material is adhered. If the rotation speed (swivel speed) of the crushing roller remains the same even if the amount of adhesion increases, the pressing force by the crushing roller remains constant, and the pressure in the layer thickness direction increased due to adhesion decreases, It is presumed that the total pulverization amount and the pulverization amount of fine powder are reduced (decrease in fineness). When the rotational force shortage of the grinding roller becomes excessive, the vibration of the roller mill increases. In order to maintain the original grinding amount and fineness, it is necessary to adjust the roller rotation speed in accordance with the layer thickness. For this reason, increasing the rotation speed increases the total grinding amount and fineness, As the shaft current increases, the power cost increases.

  This phenomenon is the same as the vertical roller mill, but from the viewpoint of the stability of the crushing operation, it is not necessary to set the initial clearance in the crushing operation by the centrifugal roller mill, unlike the vertical roller mill, and the layer thickness is determined by natural contact. Therefore, it is assumed that the load resistance is small and that stable operation is possible compared to the vertical roller mill. In the vertical roller mill, in order to apply surface pressure to the pulverizing roller, it is necessary to set an initial gap between the pulverizing roller and the rotary table, which causes a problem when the adhesive raw material is pulverized.

  However, even in the case of a centrifugal roller mill, if the raw material adhering to the grinding roller mill or bull ring is continuously removed, the increase in the layer thickness is suppressed, and the pressing pressure and friction force applied at the same rotational speed are constant. As a result, the amount of tall tar and the amount of fine powder are maintained, and an increase in shaft current is considered to be suppressed because an increase in load resistance is avoided, thereby reducing the power cost of the roller mill. It becomes possible. Therefore, it is effective to form a wedge-shaped groove on the crushing roller and the bull ring of the centrifugal roller mill and remove the raw material adhering to those crushing surfaces.

  The cross-sectional shape of the slit groove is basically a wedge shape formed by a forward inclined inner surface on the downstream side in the movement direction (front side) and a vertical inner surface on the upstream side in the movement direction (rear side). It does not have to be a vertical plane, and it does not matter that the inclination angle from the vertical plane is in the range of 0 ± 15 degrees (see FIG. 8). If the forward inclination angle of the vertical inner surface to the upstream side in the movement direction is too large, the pulverized raw material after scraping with the rear edge tends to adhere to the wedge-shaped groove and tends to be difficult to discharge to the outside. Occurs. On the contrary, if the backward inclination angle of the vertical inner surface toward the upstream side (rear side) in the movement direction is too large, the scraping effect of limestone and other adhesive raw materials is reduced, and the effective crushing area is also lowered.

  The inclination angle θ2 from the vertical plane on the forward inclined inner surface on the downstream side (front side) in the movement direction is preferably 60 ° ± 15 °, particularly preferably 45 ° or more and 70 ° or less. If this inclination angle is too small, that is, if the forward inclination of the downstream inner surface is too weak, the effect of scratching by the rear edge will decrease, and conversely if the forward inclination is too strong, the effective crushing area will decrease. However, a decrease in grinding efficiency becomes a problem.

  In addition, it is not necessary that the forward inclined inner surface on the downstream side (front side) in the movement direction and the vertical inner side surface on the upstream side (rear side) in the movement direction are directly joined at the groove bottom, and a slight flat shape is formed between both inner side surfaces There may be no interposition of the bottom surface.

  The crushing surface member of the present invention is very effective for pulverizing a raw material such as limestone that is easily adhered, but is also effective for pulverizing coal or the like that has increased adhesion due to containing a large amount of moisture.

  In the crushing surface member of the present invention, the slit groove formed on the surface thereof is a wedge-shaped groove in which the inner surface on the downstream side in the movement direction (front side) is inclined forward in the movement direction on the downstream side (front side), At the rear edge on the upstream side (rear side) in the movement direction, excessively crushed raw material adhering to the opposing crushing surface is effectively scraped off, and to the downstream side (front side) in the movement direction of the scraped pulverized raw material Is easy to avoid and the accumulation of raw material in the groove is effectively avoided. Savings and, in turn, reduction of grinding costs.

(A) (b) is the elevation which showed the crushing surface member of this invention about the trapezoid type | mold roller of a vertical mill roller. (A) is an AA line section arrow figure in Drawing 1 (a) (b), and (b) is a BB line section arrow figure in Drawing 1 (a) (b). It is the elevation which showed the crushing surface member of this invention about the tire flat type roller of a vertical roller mill. It is the elevation which showed the crushing surface member of this invention about the tire convex roller of a vertical roller mill. It is a block diagram of the experimental small crusher. It is a vertical side view which shows a table groove | channel shape. (A) is a top view which shows a table groove | channel shape, (b) is CC sectional arrow drawing in (a). (A)-(c) is sectional drawing which shows a wedge groove shape. (A)-(c) is the elevation which showed the crushing surface member of this invention about the crushing roller of a centrifugal mill roller. It is the elevation which showed the detail of the outer peripheral surface shape in the same grinding | pulverization roller about the roller with a right angle slit groove | channel of FIG.9 (b). It is a cross-sectional top view which shows the detailed shape of the right angle slit groove | channel in the roller with the same right angle slit groove | channel.

  Embodiments of the present invention will be described below with reference to the drawings.

  Each of the vertical mill rollers shown in FIGS. 1 to 4 is a grinding roller used for the vertical mill roller.

  The vertical mill roller shown in FIG. 1 is a trapezoidal roller 10 used for a vertical mill roller called a Roche mill. In the trapezoidal roller 10 shown in FIG. 1A, a plurality of screw grooves 11 are formed on the entire outer peripheral surface 12 at equal intervals in the roller axis direction. The inclination direction of the screw groove 11 is a raw material discharge direction in which the pulverized raw material is positively transferred to the outer peripheral side as it rotates, and the inclination angle is 67.5 ° represented by an inclination angle θ1 with respect to the roller shaft here. The inclination angle with respect to the roller circumferential direction is 22.5 °.

  On the other hand, in the trapezoidal roller 10 shown in FIG. 1 (b), the outer peripheral surface 12 is roughly divided into a main crushing surface 12A on the large diameter side and other portions. The main crushing surface 12A has a smooth surface. In portions other than the main crushing surface 12A, a plurality of screw grooves 11 are formed at equal intervals in the roller axis direction. The inclination direction of the screw groove 11 is a raw material discharge direction in which the pulverized raw material is positively transferred to the outer peripheral side as it rotates and is sent to the main surface pulverized surface 12A. The inclination angle here is an inclination angle θ1 with respect to the roller shaft. The angle of inclination with respect to the roller circumferential direction is 22.5 °.

  That is, the outer peripheral surface 12 of the trapezoidal roller 10 shown in FIG. 1B is a raw material transfer surface provided with a smooth main crushing surface 12A on the large diameter side and a screw groove 11 in the raw material discharge direction on the small diameter side. 12B.

  Here, the main crushing surface 12A is defined as a region in which wear of 2/3 or more of the maximum wear amount of the roller outer peripheral surface 12 occurs, and the axial length of the main crushing surface 12A in the roller, that is, the main crushing surface 12A. The lateral width of the trapezoidal roller is usually about 30 to 40% of the entire width of the roller.

  In any trapezoidal roller 10, the screw groove 11 has an inner side surface 11 </ b> A on the downstream side (front side) in the roller rotation direction as shown in FIGS. 2A and 2B. This is a wedge-shaped groove having a cross-shaped letter shape that is inclined forward to the upstream side (front side) with respect to the (perpendicular surface) and the inner side surface 11B on the upstream side (rear side) in the roller rotation direction is a vertical surface. The forward inclination angle θ2 with respect to the vertical surface of the inner surface on the downstream side (front side) in the roller rotation direction in the wedge-shaped groove is about 63 ° here.

  The vertical mill roller shown in FIG. 3 is a flat roller 30 (D / R = 4) which is a tire type roller and has a large curvature. In the flat tire roller 30, a plurality of screw grooves 31 are formed on the entire outer peripheral surface 32 at equal intervals in the roller axial direction. The inclination direction of the screw groove 31 is a direction in which the pulverized raw material is scraped back to the center side with rotation, and the inclination angle here is 67.5 ° expressed by the inclination angle θ1 with respect to the roller shaft, and the inclination with respect to the roller circumferential direction. The angle is 22.5 °.

  Also in this flat tire type roller 30, the screw groove 31 has an inner surface 31 </ b> A on the downstream side (front side) in the roller rotation direction inclined forward to the downstream side (front side) with respect to the vertical surface, and the upstream side in the roller rotation direction ( This is a wedge-shaped groove having a cross-sectionally-letter shape in which the rear inner surface 31B is a vertical surface (see FIG. 2). Here, the forward inclination angle θ2 with respect to the vertical surface of the inner surface on the downstream side (front side) in the roller rotation direction in the wedge-shaped groove is about 63 °.

  The vertical mill roller shown in FIG. 4 is a convex roller 20 (D / R = 5) which is a tire type roller and has a small curvature. In the tire convex roller 20, a plurality of screw grooves 21 are formed on the entire outer peripheral surface 22 at equal intervals in the roller axial direction. The inclination direction of the screw groove 21 is a raw material discharge direction in which the pulverized raw material is positively transferred to the outer peripheral side as it rotates, and the inclination angle is 85 ° as represented by an inclination angle θ1 with respect to the roller shaft here. The inclination angle with respect to the direction is 5 °.

  Also in the tire convex roller 20, the screw groove 21 has an inner surface 21 </ b> A on the downstream side (front side) in the roller rotation direction inclined forward to the downstream side (front side) with respect to the vertical surface, and the upstream side in the roller rotation direction ( This is a wedge-shaped groove having a cross-sectional letter shape in which the inner side surface 21B on the rear side is a vertical surface (see FIG. 2). The forward inclination angle θ2 with respect to the vertical surface of the inner surface on the downstream side (front side) in the roller rotation direction in the wedge-shaped groove is about 63 ° here.

  In order to investigate the effectiveness of the present invention, an experimental small pulverizer was prepared assuming a Roche mill with a trapezoidal roller, which is a kind of vertical roller mill. As shown in FIG. 5, this pulverizer has a structure in which the pulverizing roller 2 faces the outer peripheral surface of the horizontal rotary table 1 as a base member. The crushing roller 2 is a truncated cone-shaped trapezoidal roller, and is inclined so that the large diameter side is directed to the outer peripheral side and the small diameter side is directed to the central side, and the surface facing the table 1 is horizontal. Since it was an experimental machine, the number of rollers was one.

  A plurality of screw grooves 7 are provided on the outer peripheral surface of the grinding roller. The plurality of screw grooves 7 form grooves at right angles to the roller shaft, and feed limestone into a crushing chamber formed by a rotating table with coal as it rotates.

  In the rotary table 1, the outer peripheral portion facing the crushing roller 2 becomes an annular crushing portion 3, and the annular crushing portion 3 is a test machine, and thus can be attached to and detached from the table body 4. As the crushing portion 3, an annular smooth surface table having a flat surface, an annular right slit groove table provided with slit grooves perpendicular to the table rotation direction on the surface, and as shown in FIG. Three types of right-angle slit groove tables with acute edges were prepared by tilting backward toward the upstream side (rear side) in the rotational direction and making the forward edge 8 downstream (front side) in the rotational direction acute. The backward tilt angle of the right-angle slit groove 6 with an acute edge is 60 °, and the angle θ4 of the front edge is also an acute angle of 60 °.

  Further, in some right angle slit groove tables, as shown in FIGS. 7A and 7B, the right angle slit groove 6 perpendicular to the crushing surface is moved in the raw material discharge direction with respect to the radial line perpendicular to the rotation direction. While changing to a screw groove inclined at an angle θ3 of 67.5 °, the inner surface on the downstream side (front side) in the table rotation direction tilts forward to the downstream side (front side) with respect to the vertical surface, and the upstream side in the table rotation direction ( A wedge-shaped groove having a cross-sectionally-letter shape in which the inner surface on the rear side is a vertical surface. The forward inclination angle θ5 with respect to the vertical surface of the inner surface on the downstream side (front side) in the table rotation direction of the wedge-shaped groove is about 63 ° here. Slit grooves other than the wedge-shaped grooves are concave cross-sectional grooves.

  The crushing roller 2 is attached to the support mechanism 5 so as to be rotatable and movable up and down so that the clearance with the crushing unit 3 can be arbitrarily adjusted. Further, in order to apply a predetermined pressing force to the pulverized raw material, the pulverizing roller 2 is urged by a spring in a direction to be pressed against the crushing portion 3.

  As the rotary table 1 rotates, the rotary table 1 and the crushing roller 2 perform a relative turning motion. In this experiment, in order to confirm the pulverization performance of the various pulverizing rollers themselves, no classification device using pulverized coal air is installed. Therefore, since the pulverized coal is discharged from the inside of the rotary table to the outside due to the discharge capacity of the roller and the centrifugal force of the table rotation, a collection container that can completely collect the discharged coal is installed outside the rotary table. did.

  The Rochemill compact tester was designed so that not only the trapezoidal roller shown in FIGS. 1 and 2 but also the tire table shown in FIGS. 3 and 4 can be attached by removing the table 3. Naturally, the grinding roller 2 attached to the support mechanism 5 can be replaced with a tire-type grinding roller. It is designed so that all types of rollers and tables can be tested with a single testing machine. Further details of the testing machine are as follows.

Roller dimensions:
Trapezoidal roller Large diameter: 200mm, Small diameter: 170mm, Width 57mm
Tire type roller D / R = 4.0 Large diameter: 200 mm, tire R: 50 mm, width 74 mm
Tire type roller D / R = 5.0 Large diameter: 200 mm, tire R: 40 mm, width 66 mm

Table outer diameter:
Trapezoidal roller outer diameter: 410 mm, inner diameter: 280 mm,
Tire type roller D / R = 4.0 Outer diameter: 420 mm, inner diameter: 220 mm, groove R: 60 mm Tire type roller D / R = 5.0 Outer diameter: 410 mm, inner diameter: 230 mm, groove R: 50 mm

Peripheral speed: (counterclockwise rotation)
Trapezoidal roller 30 RPM
Tire type roller D / R = 5.0 30 RPM
Tire type roller D / R = 4.0 30 RPM

Roller pressure:
Trapezoidal roller 11.8kg and 23.5kg
Tire type roller 23.5kg

Clearance between roller and table: 0mm
Test time: 30 minutes
Limestone supply : +/- 1500 g / 30 minutes
Limestone supply method : Continuous supply screw feeder method
Temperature and humidity: 8-15 ° C, 40-70%

Limestone used in the test Particle size: 1-3mm
Particle size distribution: The particle size distribution is measured after drying for 30 minutes.
More than 10 mesh 46.0g
More than 16 mesh 44.0g
More than 30 mesh 9.0g
60 mesh or more Tr
P 0.5g

  In the experimental pulverizer, the amount of limestone discharged to the outer periphery of the table, the remaining amount of limestone in the table, the passage of 200 mesh, and the weight ratio of particles of −235 mesh under the total pulverization amount were investigated. In this experiment, for the sake of convenience, only one crushing roller is used for crushing. In the actual machine, 2 to 3 rollers are used, and a classification device for collecting fine powder is installed. A numerical value completely different from the amount of fine powder pulverized obtained with an actual machine is shown.

  In the particle size measurement, after the 30-minute grinding test, the entire amount of limestone discharged from the table to the collector was accurately collected, and the limestone remaining in the table was also accurately collected. After measuring the weight of each collected limestone, three samples were collected for particle size measurement from arbitrary locations of the collected limestone. In order to ensure accuracy, the average value of three data was adopted for the particle size measurement results. The combination of each crushing roller and the table crushing surface is as follows.

A) Combinations of trapezoidal crushing rollers are as follows.
Roller crushing surface shape table Crushing surface shape Roller surface pressure
1) Smooth surface roller + Smooth surface table 23.5Kg
2) 67.5 degree discharge direction concave screw groove roller (effective crushing area 84%) + concave right angle slit groove, groove angle 60 degree acute angle 23.5Kg
Note) This is when the concave screw groove is attached to the entire surface of the roller.
3) 67.5 degree discharge direction concave screw groove roller (effective crushing area 89%) + concave right angle slit groove, groove angle 60 degree acute angle 23.5Kg
Note) The main pulverized surface is a smooth surface, and other crushing surfaces are provided with concave screw grooves.
4) 67.5 degree discharge direction concave screw groove roller (effective crushing area 84%) + concave right angle slit groove 23.5Kg
Note) This is when the concave screw groove is attached to the entire surface of the roller.
5) 67.5 degree discharge direction concave screw groove roller (effective crushing area 84%) + concave right angle slit groove, groove angle 60 degree acute angle 11.8Kg
Note) This is when the concave screw groove is attached to the entire surface of the roller.
6) 67.5 degree discharge direction 11 rows wedge-type screw groove roller (effective crushing area 75%) + concave right angle slit groove, groove angle 60 degree acute angle 11.8Kg
Note) The main pulverized surface is a smooth surface, and the other crushed surfaces are provided with wedge-shaped screw grooves.
7) 67.5 degree discharge direction 11 rows wedge type screw groove roller (effective crushing area 66%) + right angle slit groove 60 degree acute angle 11.8Kg
Note) When wedge-shaped screw grooves are attached to the entire roller surface.
8) 67.5 degree discharge direction 11 rows wedge-shaped screw groove roller (effective crushing area 75%) + smooth surface 11.8 kg
Note) The main pulverized surface is a smooth surface, and the other crushed surfaces are provided with wedge-shaped screw grooves.
9) Smooth surface roller + Total crushing surface 67.5 degree discharge direction 11.8kg
26 rows of wedge-shaped screw grooves (effective crushing area 78%)
Note) When the wedge-shaped screw groove is attached to the entire crushing surface of the table.
10) Smooth surface roller +67.5 degree discharge direction 26 rows 11.8kg
Wedge-type screw groove (effective crushing area 83%)
Note) This is the case where the main crushing surface of the table (outer peripheral side 1/3 width) is a smooth surface and the remaining 2/3 width crushing surface is provided with a wedge-type screw groove.

  The power consumption of a small crushing tester was measured. The small pulverizer for experiments is 3 phase 220V and power consumption is 750 W / H. The power measuring instrument used is a clamp on power high tester 3168 type manufactured by Hioki Electric Co., Ltd. The power consumption is an average value of numerical values measured in units of one second. In this experiment, an average value for 30 minutes was measured. For comparison of power consumption, the power consumption consumed by the combination of the existing smooth surface roller and the smooth surface table was measured, and the power consumption consumed by the combination with various crushing surface shapes was compared.

  More specifically, the total pulverization amount for 200 mesh under was measured within 30 minutes of the pulverization test time, and the power consumption (Wh) required for the pulverization was measured. The numerical value obtained by dividing the measured power consumption by the total pulverization amount under 200 mesh was used as the power unit, and compared with the numerical values obtained for each crushing surface combination.

  The crushing test by the crushing surface member combination of the test numbers 1-10 was done, and the electric power basic unit was compared. Tables 1 and 2 show the results of obtaining the most excellent combinations of crushing surface members. In test numbers 1 to 4, the roller pressing force was set to 23.5 kg, and in test numbers 5 to 10, it was set to about 18.5 kg.

  The crushing surface of the crushing roller is a smooth surface in Experiments 1, 9, and 10, and in Experiments 2 to 5, a crushing surface having a concave screw groove with a crushed raw material transferred in the discharge direction and a raw material transfer angle of 67.5 degrees. In No. 8, there are three types of crushing surfaces having wedge-shaped (Le-shaped) screw grooves in which the pulverized raw material is similarly transferred in the discharge direction and the raw material transfer angle is 67.5 degrees.

  The crushing table is a smooth surface in Experiment 1 and Experiment 7, a crushing surface having a concave slit groove perpendicular to the table rotation direction in Experiment 4, and a right-angle slit groove in Experiments 2, 3, 5, 6, and 8, but a concave groove. Crushing surface having a right angle slit groove (Fig. 6) with an acute angle edge that is inclined backward to the upstream side (rear side) in the rotational direction and the leading edge on the downstream side (front side) in the rotational direction has an acute angle of 60 °. A crushing surface having a wedge-shaped screw groove with a raw material transfer angle of 67.5 degrees on the entire surface, transferring the pulverized raw material in the discharge direction, in Experiment 10, the 1/3 region on the outer peripheral side is a smooth surface, and the remaining 2/3 region. There are five types of composite crushing surfaces having wedge-shaped screw grooves in which the pulverized raw material is transferred in the discharge direction and the raw material transfer angle is 67.5 degrees.

  Regarding the crushing roller, among the three types of crushing surface shapes, with a wedge-shaped screw groove is the largest amount of fine powder pulverization with 200 mesh under, and the roller surface pressure is 1 compared with a simple concave screw groove with the same transfer angle. In spite of the reduction to / 2, the pulverized amount of fine powder was overwhelmingly larger than that with a concave screw groove obtained at twice the surface pressure, and the surface pressure was low, so the power consumption was also small. The crushing surface member that gave the worst results was an existing smooth surface roller.

  Regarding the pulverization table, fine powders on the smooth surface in Experiment 7 and the hybrid surface in which the main crushing surface in Experiment 10 is a smooth surface and the inner material scraping surface is a 67.5 degree discharge direction wedge-shaped screw groove surface. The amount of grinding was the largest. This means that whether one is a roller or a table, the combination in which one is a wedge-shaped groove and the other is a smooth surface will maximize the pulverization amount of fine powder. In addition, it was found that the importance of either the crushing roller or the rotary table that the main crushing surface is a smooth surface. That is, in Experiments 9 and 10, the grinding roller has a smooth surface, and the rotary table of Experiment 9 has a wedge-shaped groove on the entire surface, and the effective crushing area ratio is 78%, whereas the rotation of Experiment 10 In the table, since the main crushing surface was smooth, the effective crushing area ratio increased to 83%. The test result showed that the fine powder pulverization amount in Experiment 10 was 392 g, whereas the fine powder pulverization amount in Experiment 9 was slightly reduced to 356 g. This indicates that by making the main crushing surface to be finely ground a smooth surface, the effective crushing area is increased and the amount of fine powder crushing is increased. On the other hand, both Experiment 1 and Experiment 7 are a combination with a rotary table having a smooth surface. However, in Experiment 7 using a roller having a wedge-shaped screw groove, the surface pressure is reduced to ½. As a result, the amount of fine powder collected increased by about 1.4 times, and the power consumption decreased by about 34%.

  The power consumption obtained by the combination of smooth surfaces in Experiment 1 is 0.456 Wh / g. In contrast, Experiment 10 showed the most excellent value, followed by Experiments 6, 7, and 9. The power intensity was about 0.28 to 0.30 Wh / g, about 34 to 39%. Reduction achieved. The combination of the crushing surfaces from which the most excellent power intensity was obtained is a combination of a smooth surface roller and a wedge-type screw groove table, and a combination of a wedge-type screw groove roller and a smooth surface table.

B) Combinations of the flat tire type rollers (D / R = 4.0) are as follows.
Roller crushing surface shape table Crushing surface shape Roller surface pressure
1) Smooth surface roller + Smooth surface table 23.5Kg
2) All crushing surfaces scraped back 67.5 degrees + right angle slit groove 23.5Kg
Directional concave grooved roller (effective crushing area 78%)
3) 67.5 degrees scraping of all crushing surfaces + right angle slit groove 23.5Kg
Roller with directional wedge screw grooves (14 rows) (effective crushing area 80%)
4) All crushing surfaces scraped back 67.5 degrees + smooth surface 23.5Kg
Roller with directional wedge screw grooves (14 rows) (effective crushing area 80%)
5) All crushing surfaces scraped back 67.5 degrees + right angle slit groove 23.5Kg
Roller with directional wedge-shaped screw grooves (7 rows) (effective crushing area 90%)

  The test results are shown in Table 3. The effective grinding area in the wedge-shaped groove cross section of test number 3 is 80%, and test number 5 is 90%. The former has 14 wedge-type screw grooves, while the latter has 7 threads. The effective crushing area of the latter is increased, but the number of wedge-groove screws is halved.

  The combination of the wedge type 67.5 degree roller with screw groove (14 rows) and the smooth surface table in Experiment 4 has an overwhelmingly large amount of finely pulverized 200-mesh and very little power consumption. Gave the best results. Compared with the power unit (0.67 Wh / g) of the combination of existing smooth surfaces in Experiment 1, the latter obtained 0.36 Wh / g, reducing the power unit by about 46%. This figure shows a breakthrough effect.

  Thus, the combination of the crushing surface which can obtain the most excellent electric power consumption in the vertical roller mill using the tire flat type roller is the combination of the crushing roller with a wedge type screw groove and the smooth surface table.

C) The combination in the case of a tire convex roller (D / R = 5.0) is as follows.
Roller crushing surface shape table Crushing surface shape Roller surface pressure
1) Smooth surface roller + Smooth surface table 23.5Kg
2) Total crushing surface 85 degrees discharge direction + right angle slit groove 23.5Kg
3) Roller with concave slit groove 3) Total crushing surface 85 degree discharge direction + right angle slit groove 23.5Kg
Eight-row wedge-type roller with roller groove (effective crushing area 70%)
4) Total crushing surface 85 degrees discharge direction + smooth surface table 23.5Kg
Eight-row wedge-type roller with roller groove (effective crushing area 70%)
5) Smooth roller + 67.5 degree discharge direction 23.5Kg
13 rows wedge type table with screw groove

  The test results are shown in Table 4. The effective crushing area of the wedge-shaped screw groove rollers of test numbers 3 and 4 was 70%, which was the smallest cross-sectional area among the three types of rollers. Two types of combinations: a combination of a smooth surface table and a smooth surface roller of Experiment 5 with a 85-degree discharge direction 8-row wedge-shaped grooved groove, and a combination of a smooth surface roller of Experiment 5 and a 67.5-degree discharge direction 13-row wedge-shaped screw grooved table. , The pulverization amount of the fine powder was the largest. Regarding power consumption, 0.370 Wh / g in Experiment 5 was the smallest, the next was 0.381 Wh / g in Experiment 4, and a reduction effect of about 22 to 25% was obtained as compared with Experiment 1. Although the amount of fine powder collected in Experiment 3 was almost the same as in Experiments 4 and 5, the amount of active power was significantly larger than in Experiments 4 and 5, and the power consumption rate did not decrease. The reason is presumed that in Experiment 3, both the crushing surfaces of the roller and the table are grooved, and the load resistance between the crushing surfaces facing each other during crushing is increased. The opposing crushing surfaces in Experiments 4 and 5 were smooth surfaces, and the load resistance was smaller than in Experiment 3.

  Thus, in the tire convex roller (D / R = 5.0), the combination of the wedge-shaped screw groove and the crushing surface of the smooth surface most reduced the power consumption. Even when the wedge-shaped screw groove is arranged on the table surface which is the driving wheel, the result is equal to or somewhat better than the roller. The basic unit of electric power by the combination of the existing smooth surfaces in Experiment 1 is 0.495 Wh / g. In contrast, Experiment 4 decreased to 0.381 Wh / g and Experiment 5 decreased to 0.370 Wh / g. The wedge-shaped screw groove contributed to a reduction in the power consumption of 23% to 25% compared to the former, and showed a breakthrough performance.

  In conclusion, when pulverizing raw materials that are easy to adhere to and transfer to the crushing roller or rotary table, for example, when taking limestone as a representative example, the combination of the wedge-shaped screw groove and the smooth surface improves the amount of fine powder crushing most. At the same time, the power consumption of the mill also showed a decreasing trend, and it was found that it contributed to cost reduction by reducing the power intensity.

  The wedge-shaped screw groove may be disposed on the roller, or conversely on the rotary table. In that case, the most excellent combination is a combination with a smooth surface, but a combination with a slit groove or a screw groove may be used other than the smooth surface. Although the power consumption rate is somewhat lower than the former, it is superior to the existing combination of smooth surfaces.

  The technical basis that the smooth surface is most suitable as the crushing surface facing the wedge-shaped screw groove is considered as follows.

  That is, the opposing crushing surface that increased the amount of finely pulverized powder and reduced power consumption in combination with the wedge-shaped screw groove was a smooth surface. The reason why the smooth surface was appropriate as the crushing surface shape of the table is that when the layer of limestone adhering to the rotating table is scraped with a wedge edge, the limestone with a uniform thickness over the entire circumference of the table if the opposing surface is a smooth surface. The layer can be removed, a scraped uniform thickness clearance is formed, and the new limestone that is raked again into the clearance by the grinding roller will stably stir the required amount, giving extra resistance As a result, the pulverization amount of the fine powder increases, and the power consumption tends to decrease despite the increase of the pulverization amount of the fine powder. Conventionally, when excess limestone adheres to the table, the appropriate clearance required for pulverization is not maintained, and it becomes narrower, and the amount of raw material introduced into the narrowed clearance decreases, so the pulverization amount of fine powder decreases, and the pulverization chamber In order to forcibly introduce new limestone, the load resistance increases and the power consumption increases.

  When the facing surface is a slit groove, the crushing surface is irregularly deformed like a spur gear, and the groove is filled with limestone, but it becomes difficult to scrape the limestone in a uniform layer, inevitably It becomes difficult for the clearance formed to maintain a constant distance. As a result, the new limestone that is squeezed into the crushing chamber by the crushing roller is not introduced in a uniform amount and varies, so the amount of fine powder crushing decreases, and the load resistance constantly fluctuates, resulting in power consumption It is speculated that this will tend to increase.

  The slipping slope from the rear edge to the front edge of the wedge-shaped screw groove is pushed in at the stage where the limestone cut off by the rear edge is once accumulated in the groove of this triangular section and the rear edge scrapes the limestone again after one rotation. It is estimated that the limestone is discharged to the outside in a tokoroten manner, and this is repeated continuously. Of course, the scraping effect by the rear edge improves the pulverization amount of limestone, but the effect of further promoting it is thought to be due to the action of temporarily storing the extra limestone adhering to the inside of the triangular groove. The

  The cross-sectional shape of the wedge-shaped groove in the crushing roller and the rotary table is 5 mm in depth and 10 mm in maximum width, and the forward tilt angles θθ3 and θ5 of the forward inclined inner surface on the downstream side in the rotation direction (front side) are both about 63 °. is there. The inner surface on the upstream side (rear side) in the rotational direction is perpendicular to the crushing surface, but as shown in FIGS. 8B and 8C, it is inclined toward the upstream side or downstream side in the rotational direction within a range of ± 15 ° ( As described above, it may be tilted forward or backward.

  The grinding roller shown in FIGS. 9A to 9C is a grinding roller 40 in a centrifugal roller mill. The crushing roller 40 is a horizontal roller having a substantially vertical rotating shaft, and is a cylindrical flat roller having the same outer diameter in the rotating shaft direction. The inner peripheral surface of the crushing roller 40 is a tapered surface that gradually decreases as the inner diameter goes from top to bottom.

  On the outer peripheral surface of the pulverizing roller 40 in FIG. 9A, inclined slit grooves 41 having a relatively steep inclination having an inclination angle θ6 of 45 degrees or more and less than 90 degrees with respect to the rotation direction are provided at predetermined intervals in the rotation direction. . 9B, slit grooves 42 perpendicular to the rotation direction are provided at predetermined intervals in the rotation direction on the outer peripheral surface of the crushing roller 40 in FIG. A relatively steep inclined slit groove 41 having an inclination angle θ6 with respect to the rotation direction of 45 degrees or more and less than 90 degrees is provided on the outer peripheral surface of the crushing roller 40 of FIG. . The slit grooves 41 and 42 are formed by coating the hardened metal except for the slit grooves 41 and 42 when forming the hardened metal layer 43 on the outer periphery of the roller, or by gouging the hardened metal layer coated on the entire circumference. This is done by removing it.

  The inclination direction of the inclined slit groove 41 is different between the crushing roller 40 in FIG. 9A and the crushing roller 40 in FIG. 9C. In the pulverizing roller 40 of FIG. 9A, the inclined direction of the inclined slit groove 41 is a raw material discharge direction for scraping the pulverized raw material upward as the roller rotates, and the raw material between the pulverizing roller and the bull ring. Since the layer thickness tends to decrease, it is suitable for avoiding excessive pulverization when the raw material particles are fine and increasing the pulverization amount. In the crushing roller 40 of FIG. 9C, the inclination direction of the inclined slit groove 41 is a raw material staying direction that pushes down the crushing raw material downward as the roller rotates, and the raw material layer between the crushing roller and the bull ring Since the thickness tends to increase, it is suitable for finely pulverizing a raw material having a rough roughness. Normally, a right angle slit 42 employed in the crushing roller 40 of FIG. 9B is formed.

  A demonstration experiment of the wedge-shaped groove effect in a centrifugal roller mill was performed using an actual machine. The specifications of the actual machine used are as follows.

Roller size 490mm diameter x 230mm width (smooth surface)
Number of rollers 5 bull rings Inner diameter: 1525mm (smooth surface)
Grinding ability +/- 15 tons / hour Raw material for grinding Tancar (under 10mm)
Mill primary input 3300V mill power Mill power 135kW

  In the case of an existing centrifugal roller mill having a crushing roller (smooth surface roller) whose outer peripheral crushing surface is a smooth surface and a bull ring whose inner peripheral crushing surface is a smooth surface, the total crushing amount is about 15 tons, of which 200 mesh The under amount was about 9.75 tons at about 65%, and the 350 mesh under amount was about 5.25 tons at about 35%.

  Instead of a smooth surface roller, a wedge-shaped grooved roller with a right-angle slit wedge-shaped groove with a letter-shaped cross section is attached to the outer crushing surface, and the bull ring is attached to a centrifugal roller mill with the inner crushing surface remaining smooth. The same tancal pulverization was performed. The specifications of the wedge-shaped groove are 30 grooves, groove width w'10 mm, groove depth D5 mm, and the width W50 mm of the smooth surface portion sandwiched between adjacent slit grooves.

  By changing to a wedge-shaped grooved roller, the amount of grinding per unit time increased by about 18% to 17.7 tons / hour. Among them, the 200 mesh under amount increased to about 11.5 tons, and the 350 mesh under amount increased to about 6.2 tons. The mill shaft current did not change, and both mills were about 30A. The power consumption of both mills is also P = √3 × 3300 V × 30 A × 0.8 = 137.2 kWh. The reason for this is that since the tangles that had adhered to the inner surface of the bull ring were removed by the wedge-shaped grooves, the thickness of the tangal layer was reduced, and the roller pressure in the layer thickness direction increased naturally even at the same roller rotation speed. As a result, the amount of pulverization is estimated to increase by about 18%.

  The reason why the mill shaft current was the same between the roller mill with the smooth surface roller and the roller mill with the wedge-shaped grooved roller is that extra tancals attached to the bull ring in the conventional smooth surface roller and the layer thickness increased. As a result, the shaft current increases due to an increase in the shaft current due to an increase in rotational load resistance on the roller, and an increase in the work caused by scraping off the tangles that have adhered to the bull ring in the wedge-shaped grooved roller. It is presumed that the change in the roller mill shaft current did not change because the increase in current almost antagonized. For this reason, if the rotational speed of the wedge-shaped groove roller is reduced to match the quantity corresponding to the pulverization amount in the case of the smooth surface roller, it is assumed that the axial current is reduced more than the current state, and the power consumption of the mill Is expected to decrease compared to a smooth surface roller.

  Calculate the amount of increase in pulverization per year and the reduction in power costs. First, regarding the increase in the pulverization amount, the mill operation time for one year is set to 2350 hours. The annual pulverization rate of Tankar is 15 tons / hour x 2350 hours = 35250 tons for smooth surface rollers, and 17.7 tons / hour x 2350 hours = 41595 tons for wedge-shaped grooved rollers. Increase 6345 tons. Regarding the power reduction cost, in the case of the wedge-shaped grooved roller, assuming that the same grinding amount as 15 tons / hour of the existing smooth surface roller is ground, the grinding time is shortened by 6345 tons / 15 = 423 hours. That is, the same amount can be crushed in 1927 hours.

  And when calculating at night electricity consumption rate: @ ¥ 9.5 / kWh, the annual electricity consumption fee is 137.2 kWh × 2350 hours×@¥9.5/kWh≒¥306.60 million for the existing smooth surface roller. On the other hand, in the case of a wedge-shaped grooved roller, it is 137.2 kWh × 1927 hours × @ ¥ 9.5 / kWh≈ ¥ 25,110,000. That is, it is possible to reduce the power cost by ¥ 550,000 per year. Further, when calculated by using the daytime power consumption rate: @ ¥ 17.5 / kWh, the annual power consumption reduction is ¥ 550,000 × 17.5 / 9.5 = ¥ 1,0110,000.

  Regarding the dimensions of the wedge-shaped groove, those which satisfy the following conditions are preferable. If the depth D of the wedge-shaped groove is too shallow, the scraping effect is reduced and the inside of the groove is easily filled with tangles. On the other hand, if the depth is too deep, the tangals will fit in the grooves, the edges will be exposed to the crushing surface, and metal touch will easily occur between the opposing surfaces, and noise will tend to be intense. If the width w 'of the wedge-shaped groove is too narrow, the space for storing the tangals in the groove is reduced, and the scraping effect of the wedge-shaped groove is reduced. On the other hand, if it is too wide, the area of the smooth surface that contributes to pulverization decreases, and the amount of pulverization tends to decrease. W / w 'is the reciprocal of the occupation ratio of the wedge-shaped groove on the roller surface. If this is too small, the number of wedge-shaped grooves increases and the scraping effect is promoted, but the effective crushing area contributing to the original crushing tends to decrease. If this is too large, the effective crushing area increases, but the scraping effect tends to decrease.

7.5mm ≦ D ≦ 15mm
1.5D ≦ w ′ ≦ 2D
2.0 ≦ W / w ′ ≦ 3.0

10 Vertical mill roller (trapezoidal roller)
11 Screw groove (wedge groove)
11A Inner side surface on the upstream side in the rotational direction 11B Inner side surface on the downstream side in the rotational direction 12 Outer peripheral surface 12A Main crushing surface 12B Raw material transfer surface 12C Raw material engagement surface 20 Vertical mill roller (tire convex roller)
21 Screw groove (wedge groove)
22 outer peripheral surface 22A main crushing surface 22B material transfer surface 30 vertical mill roller (flat tire roller)
31 Screw groove (wedge groove)
32 Outer peripheral surface 32A Main crushing surface 32B Raw material transfer surface 40 Grinding rollers 41 and 42 in a centrifugal roller mill Slit grooves (wedge-shaped grooves)
43 Hardened metal layer

Claims (5)

  In the crushing surface member that crushes by crushing the pulverized raw material between the opposed surfaces by the synchronous movement of the opposed crushing surfaces, the material crushing grooves intersecting the movement direction are provided on the raw material crushing surface at predetermined intervals in the movement direction. A crushing surface member in which the cross-sectional shape of each groove is a wedge shape in which the inner surface on the downstream side in the movement direction is inclined forward toward the downstream side in the movement direction.   The crushing surface member according to claim 1, wherein the crushing surface member is a crushing roller or a rotary table in a vertical roller mill, or a crushing roller or a bull ring in a centrifugal roller mill.   The crushing surface member according to claim 2, wherein a wedge-shaped groove is formed on one surface of the crushing roller or the rotary table or one surface of the crushing roller or the bull ring, and the other surface is a smooth surface. .   The crushing surface member according to any one of claims 1 to 3, wherein the forward tilt angle from the vertical surface on the inner surface on the downstream side in the movement direction is 60 ± 15 degrees, and from the vertical surface on the inner surface on the upstream side in the movement direction. The crushing surface member whose inclination angle is 0 ± 15 degrees. The crushing surface member according to claim 3 or 4, wherein the crushing surface member is a rotary table in a vertical roller mill, the main crushing surface existing on the outer periphery of the table crushing surface is a smooth surface, and other than the main crushing surface. A crushing surface member in which a wedge-shaped material biting groove inclined with respect to the table motion direction is formed on the crushing surface.

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